Set a question as extra credit in a Test or Quiz
From EdTech Help
Extra Credit is an option for every question type in a test or quiz. Best practice is to set the question as extra credit before you publish the assessment, however you can indicate a question as extra credit after publishing by retracting and republishing.
This option is available in the question settings of a Test or Quiz. Selecting this option lets you mark a question as extra credit. This means that the points awarded for this question are not counted as part of the "total points" for the assessment and there are no points deducted for skipping this question or answering incorrectly. However, users answering correctly will receive the question point value added on top of their total points earned in the assessment.