Download Microsoft Authenticator - Microsoft Support
The Microsoft Authenticator app helps you sign into your accounts when you're using two-step verification.
Set up your Microsoft 365 sign-in for multi-factor authentication
By setting up MFA, you add an extra layer of security to your Microsoft 365 account sign-in. For example, you first enter your password and, when prompted, you also type a dynamically generated verification code provided by an authenticator app or sent to your phone.
Applies To:
Office for business, Microsoft 365 admin
What is: Multifactor Authentication - Microsoft Support
A factor in authentication is a way of confirming your identity when you try to sign in. For example, a password is one kind of factor, it's a thing you know. The three most common kinds of factors are: Something you know - Like a password, or a memorized PIN.
Set up text messaging as your verification method
Set up text messaging as your verification method. You can follow these steps to add your two-factor verification and password reset methods. After you've set this up the first time, you can return to the Security info page to add, update, or delete your security information.