ok, so what is the right approch here?
Can I hide it?
For example, Main module is checking user rights to login to my app, if it fails and I give user error that he cannot login, what then? I leave the login page open?
also where can I see all the "do" or "not do" by apple?
You can safely use all the APIs in B4i. As you can see there is no API to exit an app or to hide it because it is not allowed by Apple.
You can use App.OpenUrl to open the browser with a different page and leave your app. However there is no way to return to the home screen without the user clicking on the home button.