If you have already enabled two-step authentication via SMS, a mobile app, or a hardware security key, you have the additional option of adding one or more Windows Hello-compatible devices. When signing in from these devices, you can use your fingerprint sensor or facial recognition instead of SMS, an authenticator app, or a hardware security key to complete two-step authentication.
You will not be able to use Windows Hello when signing in from a device that was not added to your account. In these cases, you will need to use SMS, your authenticator app, or a hardware security key to sign in.
The next time you sign in, you will be prompted to use Windows Hello for two-step authentication. Follow the instructions on the screen to login. If you have a hardware security key, you can still use it while being prompted to use Windows Hello. You can also cancel and opt to use a verification code instead, either through SMS or a mobile app.
Windows Hello is supported through WebAuthn, which requires a modern browser.