You can add two types of users to your SlimWiki.

Owners: Can view, edit, create teams, add users and update billing information.
Admins:  Can view, edit, create  teams and add users. (Only on paid SlimWiki accounts)
Editors:  Can view and edit all pages in  teams they are part of. 
Viewers: Can  only view pages in teams they are part of.

There can be only one Owner on the account.