How do I switch between Passcode, Face-ID, and Touch-ID?

When you sign in on the App, go to 'Profile' and then 'Security'. There you can choose whichever option you want under 'App lock'.

If an option is not avaialbe to you, there could be several reasons:

1. Your device does not support FaceID or TouchID
2. You have not activated FaceID or TouchID in your phone settings
3. Your device is not offering a biometric that is considered secure enough