How to Add Office 365 Email Account to iOS (iPhone/iPad)
1. On your mobile device, go to Settings > Passwords & Accounts
2. Select Add Account
3. Select Exchange
4. Enter your email address and provide a description for the account
5. Select Sign In to begin setting up your email account
6. Enter your email credentials and click Sign In
If you have Multi-Factor Authentication (MFA) enabled on your account, you will be prompted to provide the MFA code (this code will be sent to your mobile device).
7. Select the items to sync and the retention period (Mail Days to Sync)