
Explanation:
Only administrators (Admin1 - Application Administrator & Admin3 - Cloud application administrator) can manage/configure apps.
Name: Cloud application administrator
Description: Users in this role can add, manage, and configure enterprise applications, app registrations but will not be able to configure or manage on-premises like app proxy.
Azure AD - User settings - App registration: default is Yes (If this option is set to yes, then non- admin users may register custom-developed applications for use within this directory.)
https://docs.microsoft.com/en-us/azure/active-directory/manage-apps/add-application-portal-assign-users
https://docs.microsoft.com/en-us/azure/active-directory/develop/active-directory-how-applications-are-added