It is part of the Windows Hello biometric authentication system ... However, if you’ve set up Face Login with a compatible camera and now want to disable it, you can follow some easy steps.

If your computer has the right hardware, accessing it using your face or your fingerprint can be more secure than traditional passwords.

This means you can log in to compatible accounts or services ... your device must have an infrared (IR) camera that supports Windows Hello. Many modern laptops and tablets come with this capability.