A user account specifies that user's level of access to the device CLI.
The software uses role-based access control (RBAC) as the authorization mechanism. A role is a container for rules, which specify which commands can be executed and with which permissions. When you create a user account you need to specify a role for that account. In general, user (as opposed to user-level) refers to any account—to which any role can be assigned—user, admin, or a non-default role.