What an email client does, and why you might want one

An email client is a program or app that downloads your email from a server and stores it on your device — your computer, phone, or tablet. Instead of logging into a website every time you want to check mail, the client keeps your messages organized locally and syncs new ones automatically.

You do not need a client to read email. Gmail, Outlook.com, and Yahoo Mail all work fine in a web browser. But a client becomes useful if you manage multiple email accounts, want to read mail offline, prefer a different layout than what the website offers, or want your messages backed up on your device rather than only on a company's server.

The trade-off is that clients require setup — you have to tell them your email address, password, and the server details — and they take up storage space on your device. For most people, the web version is enough. For people who receive a lot of mail or switch between devices often, a client saves time.

Key Takeaways

  • Email clients read and store your messages on your device, letting you read mail offline and manage multiple accounts in one place.
  • Most email providers (Gmail, Outlook, Yahoo) include built-in apps for phones and tablets that work like clients without extra setup.
  • Desktop clients like Thunderbird, Apple Mail, and Outlook require you to enter your email server details, but give you more control over how mail is organized.
  • Setting up a client involves entering your email address, password, and sometimes server addresses (IMAP or SMTP), which you can usually find in your email provider's settings.
  • If a client will not connect, the most common causes are a wrong password, two-factor authentication blocking the connection, or outdated server settings.

Built-in apps that come with your email account

If you use Gmail, Outlook.com, or Yahoo Mail, you already have an official app. These are the simplest option because they require almost no setup — you log in with your email address and password, and the app handles the rest. Gmail's app, Outlook's app, and Yahoo Mail's app all sync automatically and let you read mail offline on phones and tablets.

These built-in apps are designed by the company that runs the email service, so they work smoothly with your account and include features like spam filtering and search that match what you see on the website. They also handle two-factor authentication (the extra security step where you confirm your identity with a code) without you having to do anything special.

The downside is that each app only works with one email provider. If you have a Gmail account and a work Outlook account, you need both apps. If you want everything in one place, you need a third-party client.

Desktop clients for Windows and Mac

Thunderbird is free, open-source, and works on Windows, Mac, and Linux. It handles multiple email accounts, organizes mail into folders, and lets you search across all your messages at once. Thunderbird requires you to enter your email server details manually, but for most major providers (Gmail, Outlook, Yahoo, and many others) it auto-detects them when you type your email address.

Apple Mail comes built into every Mac. It works with any email account that uses standard protocols (IMAP or POP), including Gmail, Outlook, Yahoo, and most corporate email systems. Setup is straightforward — you enter your email address and password, and Apple Mail usually finds the server settings on its own. If you use an iPhone or iPad, Apple Mail syncs across all your Apple devices.

Microsoft Outlook (the desktop version, not Outlook.com) is part of Microsoft Office and works on Windows and Mac. It is more powerful than Thunderbird or Apple Mail — it includes a calendar, task list, and contact manager alongside email — but it costs money and takes up more storage space. Outlook is common in workplaces because it integrates with Microsoft Exchange servers.

All three of these clients store mail on your device, which means your messages stay accessible even if you lose internet. They also let you organize mail into custom folders and set up rules that automatically sort incoming messages.

How to set up a desktop or third-party client

The setup process is similar across most clients. Open the client, select "Add Account" or "New Account," and enter your email address. The client will ask for your password and usually auto-detects the server settings. If it does not, you will need to find your email provider's IMAP and SMTP server addresses — these are almost always listed in your email account's settings under "Security," "Connected Apps," or "Account Settings."

For Gmail, you may need to create an app password instead of using your regular password. This is a 16-character password that Gmail generates for you, and it is required if you have two-factor authentication turned on. To create one, go to your Google Account settings, find "Security," and look for "App passwords" — it only appears if two-factor authentication is active.

For Outlook.com and Yahoo Mail, the process is similar. Both require an app password if you use two-factor authentication. You can generate one in your account security settings.

Once the client connects, it will read your existing mail from the server. This can take a few minutes if you have thousands of messages. After that, new mail arrives automatically whenever the client checks the server — usually every few minutes, depending on your settings.

IMAP versus POP: which one to choose

IMAP is the standard for most modern email clients. It keeps your mail on the server and syncs it across all your devices. If you read a message on your phone, it shows as read on your computer too. If you delete it on your computer, it disappears from your phone. IMAP is the right choice if you check email from multiple devices.

POP is older and downloads mail from the server to your device, then deletes it from the server (usually). Once mail is on your device, it stays there even if you delete it from the server. POP is useful if you want a permanent backup of your mail on one computer, but it causes problems if you use multiple devices — messages you read on your computer will not appear on your phone.

Most email providers default to IMAP, and most clients use IMAP by default. Unless you have a specific reason to use POP, choose IMAP.

Troubleshooting when a client will not connect

The most common reason a client fails to connect is an incorrect password. Check that you are using the right password for your email account, not a password for a different service. If you have forgotten your password, use your email provider's "Forgot Password" link on their login page to reset it.

If you have two-factor authentication turned on, your email provider may block the client unless you create an app password. Check your email account's security settings to see if an app password is required, and generate one if it is. Then use the app password in the client instead of your regular password.

If the password is correct and you have created an app password if needed, the problem may be outdated server settings. Check your email provider's website for the current IMAP and SMTP server addresses, and update them in the client. Server addresses sometimes change, and an old address will cause the connection to fail.

If none of these steps work, try removing the account from the client and adding it again from scratch. Sometimes a corrupted setup will not fix itself, but a fresh start will.

Mobile email apps and when to use them

Most phones and tablets come with a built-in email app. On Android, this is usually Gmail or a generic email app. On iPhone and iPad, it is Apple Mail. These built-in apps are designed to work smoothly with your device's operating system and usually require no setup beyond entering your password.

You can also install third-party apps like Thunderbird, Microsoft Outlook, or Spark. These offer more features or a different layout than the built-in app, but they take up more storage and may drain your battery faster because they check for mail more frequently.

For most people, the built-in app is the best choice. It is fast, uses less storage, and integrates with your phone's contacts and calendar. Third-party apps are worth trying if the built-in app does not have a feature you need, like the ability to snooze messages or schedule sends.

Frequently Asked Questions

Can I use the same email account in multiple clients at the same time?

Yes. If you use IMAP, the same account can be open in Thunderbird on your computer, Apple Mail on your Mac, Gmail's app on your phone, and the web version in your browser all at once. They all sync with the server, so changes in one place appear everywhere. With POP, this does not work well because each client downloads mail separately.

Will setting up a client delete my mail from the website?

No. A client downloads a copy of your mail and stores it locally. Your mail stays on the server and in the web version. If you delete a message in the client, it deletes from the server too (if you are using IMAP), but the web version will reflect that change. Your mail is not duplicated or lost.

What happens if I stop using a client?

Your mail stays on the server and remains accessible through the website. If you used IMAP, any changes you made in the client (like deleting or moving messages) are already on the server. If you used POP and downloaded mail to your computer, that mail stays on your computer but will not sync to other devices anymore.

Do I need to pay for an email client?

No. Thunderbird, Apple Mail, and the official apps from Gmail, Outlook, and Yahoo are all free. Microsoft Outlook (the desktop version) costs money as part of Microsoft Office, but it is optional. For most people, free clients are enough.

Can a client work with a corporate email account?

Usually yes, if your company uses standard email protocols like IMAP or POP. If your company uses Microsoft Exchange, Outlook (the desktop version) works best, though some other clients can connect too. Ask your IT department for the server address and whether you need an app password or special setup.