MFA for users
Multifactor authentication (MFA) provides increased security because instead of only using a password, or a code through text, a separate app on your phone is used to verify access. MFA makes it difficult for unauthorized users to sign in. When MFA is required, people in your organization can use the Microsoft Authenticator app to securely sign into Microsoft 365 on their devices.
Use the Outlook app on your devices
When MFA is enforced, the authenticator app serves as a second form of authentication. We also recommend that everyone install and use the Outlook app to access their Microsoft 365 email on their devices. See Download Microsoft Outlook for iOS and Android.
Proceed to install Microsoft 365 Apps.