The following are supported mail and calendar apps that work with 2-Step Verification (2SV):
Android
Currently the only 2SV supported app is Outlook for Android. No built-in mail or calendar apps currently support 2SV.
iOS
Outlook for iOS and Apple Mail app (on iOS 11 or later) support 2SV.
Note: If you are using the Apple Mail app, you will need to remove and re-add your account once you are enabled for 2SV for the account to function properly.