What does an admin do with a Facebook page?
Often, the management of a Facebook page is the work of a team. Admin is the top manager and manages all group settings.

Administration
- Assign admin
- Remove admin.
- Manage page settings

Management
- Approve or deny member request.
- Approve or deny post.
- Remove posts and comments.
- Remove and block people.
- Pin or unpin a post.
- View support index.

How to add an admin to the facebook page?
To be added as an administrator of a page,
- You must first select that page (or add it as an Administrator of a group, you must be a member of that group).
- To add someone as an admin of a page, they must first prefer that page.

https://www.nettel.icu/2019/04/add-admin-to-facebook-page.html