Deleting a Course
By default, a regular Instructor can't delete a course. To delete a course, you need to have System Administrator or Course Creator permissions (and Course Creators can only delete courses they created). This is a security measure because when you delete a course, you delete all the information associated with the course, including a learner's answers to surveys and quizzes for example. It is therefore recommended to hide or archive courses rather than deleting them.
As a System Administrator, in the event that you or one of your colleagues accidentally deletes a course, you may be able to restore it. Deleted courses are placed the in the Recycle Bin for a period of 1 week. You may learn more about restoring a recently delete course (or even an activity within a course) by reading the Restoring Elements in the Recycle Bin article.
Important Notes
System Administrators can delete all courses in the system.
Course Creators can only delete courses they created.
Note that when someone with a Course Creator role is enrolled in a course (even as a learner), they inherit the permissions of Course Creator. As such, when you view the list of enrolled users for any given course, the role of "Course Creator" will show up next to their name. That does not mean they can delete the course in question.
Instructors cannot delete courses.