Fingerprints are not passwords or usernames. They're another form of authentication.
Remember: MFA is a two-or-more combination of: something you know (password, pin, etc.), something you have (keycard, token, fob, etc.), something you are (fingerprint, iris scan, voice recognition, etc.), and potentially even somewhere you are (geolocation).
Remember: MFA is a two-or-more combination of: something you know (password, pin, etc.), something you have (keycard, token, fob, etc.), something you are (fingerprint, iris scan, voice recognition, etc.), and potentially even somewhere you are (geolocation).