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Step-by-step setup for desktop Outlook versions that have FILE, HOME and SEND/RECEIVE tabs on the top ribbon. The same flow as Outlook 2013 applies to versions 2016, 2019 and 2021. Screenshots show the Turkish interface.
All the values you will use during setup are below. Replace yourdomain.com with your own domain name; the username is always your full email address, not just the "name" part.
The step-by-step email setup wizard asks for your email app and address, then guides you through every screen with settings tailored to your address. We never ask for your password.
Automatic setup often guesses the wrong server for corporate addresses; we choose manual setup from the start.

With Outlook open, click the FILE tab at the top left.

On the Account Information screen that opens, click the Account Settings button, then the Account Settings... row again.

While on the Email tab, press the New... button. If you are going to edit an existing account, you can select it from the list and click Change....

Automatic setup tries to guess the server details and is often wrong. At the bottom, select Manual setup or additional server types and press Next.

From the service list, select POP or IMAP and press Next.

This screen is the heart of the setup. In the User Name field, type your full email address, not the short name. After filling it in, press the More Settings... button at the bottom right.

In the window that opens, switch to the Outgoing Server tab. Tick My outgoing server (SMTP) requires authentication and select Use same settings as my incoming mail server below it.

In the same window, switch to the Advanced tab. First choose the encrypted connection type; if the port number does not change by itself, correct it manually. When done, press OK, then Next.

Outlook first sends and receives a test message. If both rows say Completed, exit by clicking Close and Finish.
The server details are the same in all of them; only the look of the screens changes.
Outlook 365 and the new Outlook app
iOS and iPadOS Mail app
Android phones and tablets
The Mail app on Mac
Windows, Mac and Linux