I'm on Magisk v16 and I have a terminal app. I want it to require the user to use fingerprint every time this certain app requests root access. How do I do this?
I don't know about fingerprints (since I don't use them), but to make Magisk prompt to grant/deny root access to an application without saving this preference, do the following:
If you have already granted/denied root access, revoke it in Magisk Superuser settings by tapping your app and in the newly-opened list of buttons tapping "recycle bin" button.
Next time, when the you get the prompt, be sure to change the default Forever option to Once, and only then grant/deny access.
This will grant root access for this time, but won't save the preference for the app. Thus, next time you'll be given the option to grant/deny again. Just don't forget to change Forever to Once each time.