In Sphere, we have different roles available for a user. Each role provides a different access level to a user. The role of a user is determined either the moment the owner or admin sends an invite to a user/email address OR after a user was invited.
A reader can access all reports and can run / view scenarios in the media plan section which were created by an editor or admin.
An editor can create and save media plans and access all reports.
An admin user is able to manage team members and does have permission to do everything that an editor can access.
The account owner is the user that created the account. In effect, a super-user with administrative access to manage other users & also remove the account.