Fingerprint reader not working

Use lsusb to verify that you have a finger print reader connected to the USB bus. For example, on a Thinkpad T420 the fingerprint reader appears as Upek Biometric Touchchip/Touchstrip Fingerprint Sensor in the output below.

$ lsusb
Bus 002 Device 003: ID 17ef:1003 Lenovo Integrated Smart Card Reader
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 04f2:b221 Chicony Electronics Co., Ltd integrated camera
Bus 001 Device 003: ID 147e:2016 Upek Biometric Touchchip/Touchstrip Fingerprint Sensor
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

If the fingerprint reader shows up in the lsusb output, check to see if it is supported by fprint. They have a list of supported devices. Then name you found using lsusb ought to match the devices listed at https://fprint.freedesktop.org/supported-devices.html.

If it all checks out, install the fprintd package. You can do this using the commands sudo apt update && sudo apt install -y fprintd.

This will install the command line utility fprintd-enroll. This utility is used to enroll fingerprints. The fprintd package installs fprintd-list, fprintd-verify, and fprintd-delete which you can use to manage your enrolled fingerprints.

If you require a graphical user interface, you can use fingerprint gui which is not included in the Ubuntu packages and is not supported on Ubuntu 20.04 and later.

Or you may have to update the firmware per the suggestions of the answers to Synaptics 6cb:00df fingerprint sensor not working.