To show and hide the Dynamics 365 – custom app from users other than having a system administrator role, we can use the below option
Navigate to Settings – Apps
and specify either Hide / Show for all roles.
For the end-users, it will hide the app
App not listed for the user.
Users can still access the app through URL.
The same settings can be applied from the General tab of System Settings
For Dynamics 365 On-Premise, we have a similar option in the General tab of System Settings
Hope it helps..