Microsoft has recently released a new update for its beta version of Microsoft Authenticator apps for iOS and Android devices. Phone sign-in is a new, fast, and secure way to sign in to your personal Microsoft account without using a password.
When you try to login to your Microsoft Account on the web, you’ll be able to select “use an app instead”. After you select the option, you will receive the push notification on your mobile device. After unlocking your device using pin or fingerprint, you can approve this authentication for successful login. This phone-sign feature may not be available on a few devices.