Assignments
Step 1
Go to the Course Homepage
Step 2
Click the Gear Icon > Gradebook Setup
Step 3
Go to the parent category for the item you want to make extra credit and click Edit > Edit settings
Step 4
The Aggregation method must be set to Simple weighted mean of grades. Click Save changes
Step 5
Find the activity that should be graded as extra credit.
Step 6
Click Edit, then Edit settings for that activity.
Step 7
Click on Extra Credit and Save Changes. You may need to click Show More to see the extra credit option.
The value for that activity in the Max grade column will now have a + symbol, indicating extra credit value.

Quizzes
Step 1
Create a category in the grade book and name it after the quiz that has extra credit; in the settings, make sure you select Simple weighted means of grades

Step 2
Move the quiz and extra credit quiz under the category
Step 3
In the extra credit quiz, click on Edit > Edit settings
Step 4
Check the Extra credit setting and click on Save changes.

Step 5
Update the Weight on the gradebook and press Enter