Any item with a grade can be turned into an extra credit item from within the gradebook.
While any item can become an extra credit item, parts of an item cannot become extra credit. For example, it is not possible to have 1 extra credit question in quiz that is otherwise not extra credit itself.
- Open the gradebook by clicking on the Grades link in the Administration block
- Click on the Setup tab
- Locate the item you wish to make extra credit and click on Edit and select Edit settings
- Mark the Extra credit checkbox and click Save changes