In WordPress, a capability is permission given to a user. Each user of your WordPress site has a different type of permissions or capabilities. Each capability is associated with a user role such as Administrator, Editor, Author, Contributor, and Subscriber.
The capabilities control the access level of a user on a website, and they determine what actions the user can perform. For example, an Administrator can edit, publish, and delete posts, pages, and other content on the website, while a Subscriber can only view the content.
WordPress comes with default capabilities that are assigned to each user role. However, developers can add custom capabilities to create new user roles or to give specific users additional permissions. Capabilities can also be modified or removed using code or plugins.