WordPress uses a concept of Roles, designed to give the site owner the ability to control what users can and cannot do within the site. A site owner can manage the user access to such tasks as writing and editing posts, creating Pages, defining links, creating categories, moderating comments, managing plugins, managing themes, and managing other users, by assigning a specific role to each of the users.
WordPress has six pre-defined roles: Super Admin, Administrator, Editor, Author, Contributor and Subscriber. Each role is allowed to perform a set of tasks called Capabilities. There are many capabilities including “publish_posts“, “moderate_comments“, and “edit_users“. A default set of capabilities is pre-assigned to each role, but other capabilities can be assigned or removed using the add_cap() and remove_cap() functions. New roles can be introduced or removed using the add_role() and remove_role() functions.
The Super Admin role allows a user to perform all possible capabilities. Each of the other roles has a decreasing number of allowed capabilities. For instance, the Subscriber role has just the “read” capability. One particular role should not be considered to be senior to another role. Rather, consider that roles define the user’s responsibilities within the site.