Go to your iPhone or iPad's Settings > scroll down and tap Accounts & Passwords > Add Account.
Note: If you're on iOS 10, go toMail > Accounts > Add Account.
Enter your Microsoft 365, Exchange, or Outlook.com email address and a description of your account. Tap Next.
Tap Sign In.
Enter your email account password and tap Sign In.
If multi-factor authentication is enabled, verify your identity.
The Mail app may request certain permissions. Tap Accept.
Choose the services you want to sync with your iOS device and tap Save. You're done!