I am the Administrator. How do I find out the password for one of my users?
You would need that user to provide you with their password. Infusionsoft IDs are created by the user, and can technically be connected to multiple applications. An Infusionsoft ID could even be created, but not tied to logging into any application.
The only thing you can do as an admin in this context is to invalidate the user. Users have their own id/pw that can apply to multiple app invites so changing their personal password would affect their access to all but you can invalidate their access to the specific app in the Users list.