Module security
From MoodleDocs
Location: Settings > Site administration > Security > Module security
Certain activity modules may be disabled so that they do not appear in the "Add an activity" drop-down menu for teachers. The setting only applies to teachers - administrators are always able to add any activity to a course.
To disable an activity module completely, click the eye icon in the hide/show column in Settings > Site administration > Plugins > Activity modules > Manage activities.
