Users in Bynder are closely tied to permissions. Each user needs to be assigned to a user profile, and the user profile defines what the user can and cannot do in the portal.
Users are split into three categories: Light users, Regular users and Heavy users. Light can usually preview assets, but need to ask for permission to download them. Heavy users, on the other hand, are usually administrators who have the right to assign permissions to user profiles. Regular users are the users who usually have full edit, upload and download rights to assets.
It's the role of an administrator to create user accounts. S/he can also deactivate or delete accounts if necessary. Only users with active user accounts can log in.
The exact number of seats per user profile that you have at your disposal is specified in your contract.