To use an authenticator app go through the following steps:
Download a two-factor authenticator app like Microsoft Authenticator for
Windows Phone,
Android and
iOS or
Google Authenticator for
Android and
iOS.
Scan the QR Code into your two factor authenticator app.
Once you have scanned the QR code or input the key above, your two factor authentication app will provide you
with a unique code. Enter the code into the One-time Password field during login.