The following table lists the default access levels.
The limited assignee level user does not have access to the portal and does not get notifications.
To allow granular control of what a user has access, an administrator can create specific groups, and set what components someone has access. "None" hides the items from the user, "Read" provides read only access, and "Read/Write" provide full edit capability.
At any point, users can be assigned to the group via the General tab.
From a user edit screen, groups can also be added the user.