You can do that from phone settings on certain brands of android phones. I am sure Samsung has it. You can have the OS ask for unlock when opening the app, which is where the fingerprint or face id should come as selection. I am just guessing about the face unlock, I'm sure for the rest, but it could be just a choice between a pass or fingerprint. Also, you can hide the app, so it won't show anywhere unless you search for it.