Using biometric authentication and JWT token for Authorization

Hey everyone I’m a security penetration tester and I’ve been working on a security solution on how to implement biometric authentication with JWT authorization.
basically I wanna know what is the flow?
Here are my questions more specifically:

  1. where do you store the biometric information in Kotlin?
  2. how do you use refresher Token?

It doesn’t seem related to Kotlin. If you mean Android then you should look on Android forums.