Perhaps you do not want every site collection admin in all of your sites to add a particular app to their site. How do you control access to apps in your tenant?
-Go to your app catalog.
-Find the app you want to secure.
-Click on the ellipses.
-Select the ellipses after SHARE.
-Select Advanced.
-Select Shared With.

-Then select Advanced

-Then select Stop Inheriting Permissions.
-Then select the groups you do not want to be able to add the app and select Remove User Permissions.

That’s it. Now the app can only be added by the administrators/owners of the app catalog.