1. Navigate to your course

2. Select Grades from the left-hand side menu:

3. Look for the drop-down menu in the Moodle and select Gradebook Setup:

4. Look for a category folder within your gradebook:

5. Find the Edit drop-down menu that is in line with that folder/category:

6. Open the drop-down and select Hide:

 7. Your gradebook category will now appear greyed out and invisible to students:

8. To make your grade category visible again, repeat the process, but instead of selecting Hide, select Show: