Update my email settings to Exchange in Outlook on iPhone or iPad

If you migrated a POP or IMAP email account to Microsoft 365, export your previous locally saved data and set up your new account with Exchange settings. Using Exchange ensures your data — including mail, contacts and calendars — stays connected with your email and is recoverable from the server whenever needed.

Required: If you're using POP settings, data like your messages, folders, calendars, and contacts only exist on your email client and the device you use to check your email. Before switching to Exchange settings, back up your data so you can either import it into your account or reference it later. For instructions, please refer to your client provider.

Open Outlook. (Don't have the app? Download it at the iTunes App Store and follow these steps to set it up.)
In the upper-right corner, next to Inbox, open the menu, then Settings.
If you're ready to remove your POP/IMAP account, tap Accounts.
Tap the email address, and then Remove Account.
To confirm, tap Remove.
To add your Exchange account, tap Add Account.
Enter your Microsoft 365 email address, and then tap Add Account.
If your admin enabled multi-factor authentication (MFA), verify your account or set up the Authenticator app.
Enter your Microsoft 365 password, and then tap Sign In. (You might need to choose your account type as Work or school.)