There are two general Drupal roles set by default. These roles are assigned to users by the system. By assigning roles, the Drupal framework sets the limits of user access to the Drupal created website.
The first role is called Anonymous User. This is set by default to those users who are not logged in to the Drupal site. Generally, these are the general web users who visit sites. They can just view the content of the site and read them.
The other Drupal role is set by the system as Authenticated User. These users have access rights to the site as long as they log in to the administrator interface. Site administrators and managers are the primary authenticated users. They have full access and full control of the Drupal created website. They can do what they like on it even deleting the entire framework. Site administrators can also set specific roles to other authenticated users.
For example, users who have access rights can be given the role of a writer. As writers, these users can log in to the Drupal site and write articles or content for it. They can also edit or delete what they wrote. Administrators however can control the publication rights of these writers. This means another layer of Drupal role for authenticated users must be set.
In this case, Drupal site administrators can assign editor roles to some authenticated users. These users can also be called moderators or mods. Their role is to review what the writers created and edit the material for publication. Through this system, the production of quality content can be ensured.