Windows Hello For MFA

Question

Hello

From my understanding Office 365 Windows Hello can be used for MFA into Office 365.

I am just trying to understand how this works. If a user logs into the office 365 portal, how would they be prompted for MFA using Windows Hello?

Lets also take the case of if they are using their phone to check email, can Windows Hello be used to MFA?

Any details on this would be appreciated.