Apple Touch ID enables you to authenticate to a Mac operating system using the electronic fingerprint recognition feature available in Mac device. When you try to authenticate Mac device, the presented fingerprint is matched with the enrolled fingerprint. If the fingerprints match, you are authenticated.
NOTE:It is not possible to perform an initial authentication by Touch ID after boot
Perform the following steps to authenticate using the Apple Touch ID:
Place your finger on the Touch ID reader.
If the fingerprint matches with the enrolled fingerprint, the authentication is successful.