Both admins and moderators count as staff members. These two roles have different levels of access.
Admins are able to change all the settings inside the community. They have access to all data and user info. They can delete accounts from the community, changing the links and look and feel, and many more accessibilities in the admin panel.
Moderators only have access to edit the content and make sure that the posts are qualified and appropriate. They have no access to the settings of the community, and cannot delete an account from portal. Find more information in here: What are the roles and responsibilities of a community moderator?291