By default, all users inherit the global app permission policy. However, you can create custom app permission policies and apply them to users.

To create an app permission policy, follow these steps:

1. Launch the Microsoft Teams admin center (https://admin.teams.microsoft.com) and navigate to Teams apps | Permission policies.
2. Select a policy to edit or click + Add to create a new policy:

3. Under each of the following sections (Microsoft apps, Third party apps, and Tenant apps), select an option for which apps you want to allow or block, and then click Save:

Valid selections for all the drop-down menus include Allow all apps, All specific apps and block all others, Block specific apps and allow all others, and Block all apps.

4. Under Users | Users, select one or more users, and select Edit settings. Then, under App permission policy, select the permission policy to apply and click Save.

When configuring app permission policies, Microsoft refers to apps produced by Microsoft and its partners, Third party refers to apps published by other companies, and Tenant refers to custom apps that your organization has uploaded.