You can belong to several teams and thus consume apps from different teams, but you can only create and manage one (1) own team.
These options can be disabled in the Enterprise Package, so that team members invited by you do not have their own teams (thus cannot create their own apps) and can only be members of your team.
A detailed guide to user management in Open as App can be found in the article Team, users, groups, and guests | Manage user access rights
You can see in the settings in the App Client on Android or iOS which teams you are a member of.
To access the settings, proceed as follows:
- Open the left menu
- Click on "Settings"
In this view, you can see your own team (in this case your team is called "firstname.lastname@example.org") as well as other teams you have been invited by.
To leave a team, click on the "Leave" button of the respective team.
Please note that you may lose access to apps and hubs in this way.