Note: You are currently viewing documentation for Moodle 2.2. Up-to-date documentation for the latest stable version is available here: Assign roles.
To assign a role to another user, first choose the type of role you wish to assign. For example, if we wanted to assign a Course Creator role to Ali, we'd choose "Course Creator" from the drop-down list. ("Course Creator" is one of the default role types that comes with Moodle - your installation may have a modified set of roles.)
Once you have selected a role, two lists appear: the list of users who currently have that role, and the list of users who don't. We can locate Ali in the second list, and use the left-facing arrow button to add Ali's account to the list of Course Creators.