Multi-factor authentication provides more security, making it harder for an unauthorized person to use your work account. Here is how to setup the Authenticator app to work with your Microsoft 365 work account:

Once the two-factor security has been set up for your Office 365 work account you will be asked to provide a code from the Authenticator app when signing into your Office 365 account. Or, you may receive a push notification from the authenticator app asking you to approve the login. One you have approved teh login, you can access your Office 365 account.