Fingerprint Reader

Some laptops (especially those of the ThinkPad persuasion) come with an integrated fingerprint reader which can be used for authentication. Many guide expect the reader to be used in the place of a password. It is highly imperative to note: fingerprint reader technology is not considered to be secure by security experts. Fingerprints should not be substituted for passwords for any device. Passwords can be easily changed; fingers cannot. There are many known techniques to extract fingerprints from the device casing in order to gain access to the system through the fingerprint reader.

With the above paragraph being understood, it is perfectly acceptable to use a fingerprint to identify the user account before signing with key-based authentication.

Enroll a fingerprint to user
To save fingerprint with fprint you can use fprintd-enroll