Users may be added to a Moodle site in a number of ways. When user accounts are created on a site, the process is called Authentication and when users join a course, the process is called Enrolment. Normally only the administrator is allowed to add users to a site. Course teachers are only able to add students to their course and do not have permission to add users to the site. (If you’re a teacher looking for instructions on how to add students to your course, read Add students.)
Users sign up to the site themselves
If you wish people to create their own accounts on your site, you must enable Email-based self-registration. This features is disabled by default because of the possibility of spammers accessing your site.