SMS Two-Factor Authentication (2FA) is now enabled to allow you to setup your phone number to receive text messages of one-time passcode when asked to authenticate your AST O365 Account.
Setup MFA for users who are using the MS App for Self-Service Password Reset.
MFA Microsoft Authenticator App setup using only the mobile phone.
Setup Multi-Factor Authentication for AST users using the MS App which requires the mobile phone and a computer.