Types of email

"Types of email" means three different things, which is why a clear answer is hard to find. It depends on what you are actually asking:

• ✓By type of account: personal or corporate (the one that runs on your company's domain).
• ✓By server and protocol: SMTP to send; POP3 and IMAP to receive. Exchange always sneaks into this list even though it is a different animal: Microsoft's mail server, which speaks its own protocols.
• ✓By type of campaign, if we are talking about email marketing: relational, promotional and transactional. These are "the 3 types" most people are looking for.

Below you have each one explained, with what changes in practice and which suits you depending on what you do. And if you came for the third one, the warning first: splitting them into three families is not a marketing whim. It is what decides whether you need permission to write or not, and what the requirements Gmail and Outlook impose on your mail hang from.

01What types of email account are there?

Let's start at the bottom. Email accounts fall into two groups: personal and corporate.

Corporate email

Whether you run your own business, work for someone else or invoice as a freelancer, it pays not to mix the personal with the professional. If you are thinking of setting it up, we walk through it step by step in how to set up business email with your own domain. An address on your own domain says who the message is from before anyone opens it, and it draws a clean line between what is work and what is not.

Personal email

Personal email is for signing up to websites, for social media and for talking to people who do not pay your invoices. Keeping it apart from the professional one has a practical reason: when both land in the same inbox, what ends up buried under the supermarket offers is usually the work email.

02What types of email server are there?

Let's start with the technical part, clearing up one confusion: SMTP, POP3 and IMAP are not servers, they are protocols, the language email is spoken in. What splits into two groups is the job, which is why people say outgoing servers and incoming servers, even though in practice the same machine usually handles both.

Outgoing servers

The ones that get the message out of your mailbox and into the recipient's. There is only one protocol at play here.

SMTP

SMTP (Simple Mail Transfer Protocol) is the most widely used protocol. It routes your mail towards your provider's servers and then on to the recipient's account, even if they are with a different provider.

Incoming servers

The ones that store what arrives and show it to you when you open your mail. Here the choice does change how you work.

POP3

POP3 (Post Office Protocol) is one of the oldest. It downloads mail onto the device it connects from and, by default, deletes it from the server, so you cannot read it anywhere else. Almost every mail program lets you change that and keep a copy on the server, but it is a box you have to tick yourself.

IMAP

IMAP (Internet Message Access Protocol) is newer. Once delivered, the message stays on the server, so you can get at it from several devices. In exchange, it takes up space there.

Exchange

Exchange, from Microsoft, is a different beast: their in-house business mail, with its own protocols. What it adds over POP3 and IMAP is that it also syncs calendar, contacts and tasks, which neither POP3 nor IMAP do (Microsoft documentation).

The last two columns for POP3 and IMAP come from the Exchange documentation, checked on 8 September 2026: "Doesn't offer advanced collaboration features such as calendaring, contacts, and tasks". The same page adds that a POP3 or IMAP4 client does get limited access to calendar information when the mailbox sits on Exchange.

03The main email providers

For a free personal account, the choice almost always comes down to these three names. Each comes with its catch, which is what ends up deciding. There are more (iCloud, or the mailbox that already comes with your hosting if you have your own domain), but those are less chosen than handed to you along with something else.

Gmail

Gmail, Google's mail service, is one of the most popular in the world. It filters spam well and searches inside your mailbox the way Google searches, which for a ten-year archive is no small thing. Its drawback, precisely because so many people use it, is how hard it is to find a free name: if you want an account with your own name on it, you will probably have to add numbers or symbols.

Outlook

If you were born before the year 2000, chances are you have had an Outlook or even a Hotmail account. It is no longer everywhere, but it remains one of the most popular providers, and if you already work with Word and Excel, the calendar and the contacts turn up where you expect to find them.

Yahoo! Mail

Yahoo! Mail was more popular in the past, but it is still widely used, and it keeps a feature the other two do not have: disposable addresses, so you do not have to hand over your real one at every sign-up. With small print. Their help documents them for the old desktop version, and only where Yahoo Mail Plus is sold, which is not every region. There you can try up to three for free and reach 500 with the subscription (Yahoo help, checked on 8 September 2026). Watch out for one more detail. Yahoo warns that if you do not sign in to the mailbox for twelve months it is treated as inactive, stops receiving messages and deletes emails, folders and contacts. After twenty-four without signing in, it schedules the whole account for deletion (inactive mailboxes in Yahoo Mail).

04What types of email marketing can you do?

Search for "types of email marketing" and you will get lists of ten, of thirteen and of seventeen. What is happening is that they are counting campaigns instead of families. Campaigns, you can invent as many as you like. Families, there are three, and they are the ones that matter: each is sent for a different reason, and legally they split in two, with transactional on one side and the other two on the other. That second part never shows up in the lists of seventeen.

Relational emails

Relational emails build a relationship out of useful content, and they work if you know where the person receiving them stands: you do not write the same way to someone who has just subscribed as to someone who has been reading you for two years. This family covers:

• ✓Newsletter. The good old periodic send. It works when it has a reason to exist beyond reminding people you are still around.
• ✓Welcome. The first one someone gets after signing up. It arrives when the person has just remembered you exist; in our view, that is the best moment for it to be opened.
• ✓Guided start. A short series that teaches people how to use what you sell. The industry calls it onboarding.
• ✓Surveys and review requests. Asking is cheap and hardly anyone does it.
• ✓Thank-yous and milestones. The "thanks for your order" or the first year as a customer. Cheap to set up, and by our own criterion the place where writing bothers people least, because it asks for nothing back.
• ✓Re-engagement. For anyone who has not opened a thing in months, before you take them off the list.

Promotional emails

Promotional emails push towards a specific action, which is not always an immediate purchase. Segmentation decides whether they work and, in our experience, you should send considerably fewer promotional than relational ones. This family includes:

• ✓Offer or discount. The classic, and the first to burn out if you overdo it.
• ✓Launch. The notice that something now exists which did not before. We send another email beforehand warning that it is coming, so the announcement day is not the first anyone hears of it.
• ✓Seasonal campaign. Sales, back to school, Black Friday, Christmas.
• ✓Abandoned cart. It fires on its own when someone leaves something unbought. Being automatic does not make it transactional: it is promotional, and that matters for what the law demands, in section 05.
• ✓Cross-sell and upgrade. What suits someone who has already bought from you. The legal exception in article 21.2 does not look at what type of campaign it is, but at whether there is a prior contract and whether what you are offering resembles what was bought; this is the one that fits most often.
• ✓Event or webinar invitation. It promotes even when entry is free.
• ✓Free trial and downloadable content. The guide in exchange for an email address, which is how most lists get filled.

Transactional emails

Transactional emails are sent in response to something the recipient has done. You do not decide them: the person triggers them. They are these:

• ✓Order confirmation, receipt or invoice.
• ✓Dispatch and delivery notices.
• ✓Password recovery and account verification.
• ✓Appointment confirmation and reminder, at the dentist and at the garage.
• ✓Delivery of whatever someone has just asked for: the downloaded PDF, the quote requested.

They are the most boring to write and the only ones people are genuinely waiting for: someone who has just bought will go looking for that email. If you sell online and you are only going to look after one family, by our criterion look after the transactional one.

Which one fits what you want to achieve

And if you are only going to set up one send, make it an automated one. Omnisend measured 27 billion emails sent by 150,000 brands during 2025 and found that automated ones account for 2% of sends and 30% of the revenue email brings in. In a different cut of the same report, so the two pairs of figures need not add up with each other, automated mail earns 2.87 dollars per email against 0.18 for the traditional scheduled send (2026 report).

Omnisend publishes a separate count elsewhere, done over 20 billion campaign emails and 470 million automated ones: there the welcome email converts at 2.11% and the campaign at 0.08% (their email marketing benchmarks). They are two different samples and they do not add up.

What gets sent in Spain goes another way. According to Acumbamail's report on the 55,332 active accounts on its own platform during 2023 and 2024, 97.13% of the campaigns that went out of it in 2024 were newsletters (email marketing statistics in Spain, in Spanish). That 97.13% portrays the customers of one Spanish sending tool, not Spain. You also need to know what it counts, because those are campaigns and automations are counted separately: the source itself puts them at 2.24%. Even with that caveat, what the sample does support is this: among that tool's customers, the newsletter is almost the only format in use.

Both figures above should be read knowing where they come from: Omnisend and Acumbamail sell sending platforms and measure their own customers, not the market. They are useful for comparing one type of campaign against another within the same sample, which is what they are used for here, and not for working out how much email sells in Spain.

• ✓Stop a new subscriber going cold → welcome email the same day and a guided start during the first week.
• ✓Recover half-finished sales → abandoned cart, and only if that person gave you permission when they left their address: someone who abandons a cart is often not a customer yet, so there is no prior contract to lean on.
• ✓Sell more to someone who already bought → cross-sell, with the exception in article 21.2 of the LSSI on your side.
• ✓Stop people phoning to ask whether the order has shipped → well-written transactional emails.

If you would rather not set this up yourself, it is part of what we do in our marketing services: pick the family that suits you, leave the automations running and measure them.

05Which ones you can send without asking permission

This is the only part of the article that can cost you money. In Spain, commercial email is governed by article 21 of the LSSI, Law 34/2002 on information society services, and what it says is short: "The sending of advertising or promotional communications by email or other equivalent means of electronic communication that have not been previously requested or expressly authorised by their recipients is prohibited" (our translation of the consolidated text in the Spanish official gazette, in Spanish).

Applied to the three families above:

The last column summarises paragraphs 1 and 2 of article 21 of the LSSI, checked against the consolidated text in the Spanish official gazette on 8 September 2026.

There is a useful exception in paragraph 2 of the same article: if a prior contractual relationship already exists, you obtained the address lawfully and you write about similar products or services to the ones that person contracted, you can do it without asking again. You can write to someone who bought tyres from you about tyres; about life insurance, no.

There is also an obligation that does not depend on any of the above, because the same article imposes it "in every case": you have to offer a "simple and free procedure" to object, both when you collect the address and in every single email you send. In email that means including a valid address where that right can be exercised, and the law goes as far as expressly prohibiting communications that do not carry one. Whether you have consent or not.

And watch this one: a transactional email stops being transactional the moment you slip an offer into it. If you sneak a 20% discount banner into the dispatch notice, that email is now advertising and needs a permission you probably do not have.

What skipping it costs: article 38 of the LSSI classes sending without authorisation as a minor infringement, and mass sending or "persistent or systematic" sending to the same recipient as a serious one. Article 39 puts a price on them: up to 30,000 euros for a minor one, and from 30,001 to 150,000 euros for a serious one.

And now a pause, because a good deal of what you read about this quotes a law that is no longer in force. From 2002 to 2014, for almost twelve years, article 38 did give a number: sending "more than three commercial communications within one year" to the same recipient turned the infringement into a serious one. That number is gone. Law 9/2014 of 9 May, the General Telecommunications Act, which took the chance to rework the LSSI penalty regime, replaced it with effect from 11 May 2014 by "persistent or systematic", which carries no figure. We checked it wording by wording against the consolidated text in the official gazette on 7 September 2026.

This is a summary to get your bearings, not legal advice: the body that imposes these penalties in Spain is the Spanish Data Protection Agency, and not by custom. Article 43.1 of the LSSI gives it that competence for this infringement specifically. If your case has nuances, it is worth taking advice. And if you are setting up subscriber capture right now, look at the forms on your website first: we cover that in how to turn your website into a salesperson.

06What do Gmail and Outlook require for your mail to arrive?

Having permission is not enough; the mail still has to get in. Since 1 February 2024, Google requires four things from anyone sending more than 5,000 messages a day to Gmail accounts (Google's sender guidelines, checked on 8 September 2026):

• ✓Authenticate the domain with SPF and DKIM.
• ✓Publish a DMARC record too on the sending domain.
• ✓One-click unsubscribe in marketing and subscription emails.
• ✓Spam rate below 0.30%, and better below 0.10%, which is what they recommend.

Look closely at the first one, because Google's own page says two different things depending on which language you open it in. The summary matches in the three versions we checked on 8 September 2026: "All senders: SPF or DKIM. Bulk senders: SPF, DKIM, and DMARC". But in the section about the threshold, the English version asks for "SPF and DKIM email authentication for your domain" and the Spanish one, on that same line, asks for SPF or DKIM. When a source contradicts itself, the defensible move is to go with whichever demands more: if you are over 5,000 a day, set up all three. And setting up all three pays off even below the threshold, because DMARC only passes an email if an SPF or a DKIM has already passed aligned with the sender's domain (how DMARC works, in Google's help), and because Microsoft does require all three.

Microsoft came later, and stricter: it requires SPF, DKIM and DMARC from domains sending 5,000 or more emails a day since 5 May 2025 (Microsoft's announcement). It started by sending what did not comply to the junk folder and today it rejects it outright, with a 550 5.7.515 error the sender sees in their bounces (Outlook.com help, checked on 8 September 2026).

SPF, DKIM and DMARC are three entries in your domain's configuration that let the receiving mailbox check that whoever signs the email is you and not someone impersonating you. If you send 300 emails a month, the 5,000 threshold does not apply to you. But Google asks every sender for SPF or DKIM, with no threshold at all (same guidelines), and any sending platform will ask for it before letting you launch. It is an afternoon's work for whoever looks after your domain, though it is not quite set and forget: DMARC reports need looking at now and then, and SPF gets touched every time a new sending platform comes in. If your company email does not run on your own domain yet, that is the first step, and section 01 has the link to the guide that explains it.

07Measuring the channel: why email rarely gets the credit

Here is a trap that sinks email marketing budgets without anyone noticing: email brings visits and Analytics files them somewhere else. It isn't a fault in the tool, it's how it works.

Google spells it out in the Analytics help: "A session is processed as direct traffic when there is no information about the referring source" (traffic source reference, checked on 8 September 2026). And with email that is almost always the case: someone clicking from desktop Outlook or from a phone app arrives with no referrer, because the click doesn't come from a web page. The result: that visit lands in direct, the same bucket as someone typing your address by hand.

What fixes it are UTMs: parameters added to the end of every link you put in an email (utm_source, utm_medium, utm_campaign) that tell Analytics where the visit came from. Most sending platforms add them for you if you tick the box, which is why it's worth checking that box before the first send.

Without it, email works for free: it brings people in, never shows up in the report and, when the time comes to split the budget, a channel with no numbers always loses to one that has them.

08Frequently asked questions

What are the 3 types of email?

If you mean email marketing, there are three: relational (they bring content and build a relationship), promotional (they push towards a specific action) and transactional (they respond to something the recipient has done, such as a receipt or a password change). If you mean accounts, the split is in two: personal and corporate.

What are the 4 types of email?

There is no official list of four. Anyone talking about "the four types" almost always means the protocols: SMTP to send, and POP3 and IMAP to receive; the fourth that usually sneaks into the list, Exchange, is not a protocol but Microsoft's mail server. The classification that holds up works on three levels: by account, by server and by type of campaign.

What are the 5 most used emails?

There is no official list of five, just as there is none of four: it is a way of asking that has caught on in search engines. If the question is about providers, the most widespread are Gmail, Outlook, Yahoo! Mail, iCloud and the mail that comes with your own domain or hosting. If it is about types of send, in a small business the ones that are almost never missing are the order confirmation, the dispatch notice, the welcome email, the newsletter and the occasional offer.

What is email marketing?

It is using email to communicate with customers and subscribers for a commercial purpose: to sell, to build loyalty or to inform. It differs from ordinary email in that it goes to a list, it is automated and it is measured. In Spain you can only do it with people who have given you permission or who are already customers of something similar.

Do I need permission to send commercial emails in Spain?

Yes. Article 21 of Law 34/2002 (LSSI) prohibits sending advertising or promotional communications by email that have not been requested or expressly authorised. The exception is that a prior contractual relationship exists, that you obtained the address lawfully and that you write about products or services similar to the ones already contracted, always offering a simple and free way to object. Transactional emails (an invoice, a dispatch notice, a password change) are not advertising and fall outside, unless you add an offer to them.

What is the difference between a personal and a corporate email?

The corporate one runs on your company's domain (hello@yourcompany.com) and belongs to the company; the personal one is free, runs on the provider's domain (@gmail.com, @outlook.com) and belongs to whoever opened it. In practice the corporate one carries more trust and does not walk out of the company when a person does. What it does not give you on its own is deliverability: a freshly set up domain has no history, and without authentication it does not pass the checks Gmail and Outlook run before letting an email in. Google asks every sender for SPF or DKIM, and from 5,000 emails a day its summary raises the bar to SPF, DKIM and DMARC; Microsoft requires all three from that same threshold.

How many types of mail server are there?

They group into two by the job they do, outgoing and incoming, although what has names of its own are the protocols they speak. To send there is one, SMTP. To receive there are two: POP3, which downloads mail onto a single device, and IMAP, which leaves it on the server and lets you read it from several. Separately there is Exchange, Microsoft's business mail, with its own protocols that sync mail, calendar and contacts at once.

Which is the best email provider?

It depends on the use. For a personal account, Gmail and Outlook are the two most widespread. For a company, the decision is not the provider but the domain: what matters is that the address is yours. From there, entry plans hover around 6 to 7 euros per user per month. Google Workspace Business Starter is listed at 6.80 euros excluding tax on its Spanish pricing page, list price checked on 8 September 2026. Microsoft 365 Business Basic publishes its own on its pricing page: check it the day you are about to sign up, because a price expires on its own. They climb quickly as soon as you want the desktop applications, and for a freelancer or a small team the mail included with your hosting is usually enough.