Users can sign into their Microsoft accounts on a new computer by entering their username and unlocking their phones with a fingerprint or PIN. From there, you simply need to tap Authenticate when you receive a Microsoft Authenticator notification.
In an official blog post (opens in new tab), Microsoft's Alex Simons noted that the process is more secure than signing in using a password, which can be compromised and easily forgotten.
To set up Microsoft Authenticator, Microsoft says you can just select the drop-down button on your personal account tile and choose Enable phone sign-in. The company says it will automatically prompt you to set Authenticator up if you're adding a new account on an iPhone, and if you're setting up a new account on an iPhone, it will automatically set the feature up for you.
Interestingly enough, Microsoft hasn't developed a Microsoft Authenticator app for Windows phones. However, Simons said that the team will consider it if the app does well for Android and iOS users.