I'm not sure what make and model your machine is but, for the most part, 20.04 and most distros across the spectrum have a tough time supporting fingerprint sensors.
I have a Thinkpad T480 with a sensor, and have no luck with 20.04. However, 20.10 is supposed to be released on Thursday (the 22nd) and fingerprint sensor capability is reportedly prioritized. The libfprint component is supposed to be used with software and make it much easier to use a sensor.
That's one of the reasons I am switching to 20.10 for the duration of its support.
You mentioned that is doesn't show up in settings, but it shows up when running lsusb. I have tried the 20.10 Beta, and am about to install it now, and I couldn't even find it in the settings there either. Maybe that will change once the official version is released. We may have to install separate software or a driver or something though.
Another thing, and possibly the biggest: this capability is going to be backported to 20.04 eventually, probably sooner rather than later.
Hope that answers your question. I would just wait for 20.10, or for it to be integrated to 20.04.