Allow role assignments
From MoodleDocs
Location: Administration > Users > Permissions > Define roles
The Allow role assignments page is for setting which roles each role can assign other users to. These roles are also available in the "Switch role to..." drop-down menu for users with the moodle/role:switchroles capability.
Enabling teachers to assign other teachers
By default, teachers can only assign other users the roles of non-editing teachers, students and guests. If you want teachers to be able to assign other teachers in their course, you can allow the role assignment:
- Click on Permissions in the Site Administration block, then Define roles.
- Click the Allow role assignments tab.
- Click the checkbox where the teacher row and column intersect.
- Click the "Save changes" button.