Settings Quizzes
Screenshot of the Quizzes settings menu in Google FormsScreenshot by R. Krantz

Make This A Quiz:

If you have an existing Form with multiple choice options you would like to change to a self-grading quiz, simply slide the switch to "Make this a quiz"!

In order to allow auto-grading, the "Make this a quiz" switch must be turned on.

Release Grades: 

For immediate feedback of multiple choice quizzes, select "Release Grade Immediately".

If you would like to review one or more questions manually (e.g. a short answer response), choose "Later, after manual review". 

Show Respondants:

You may also choose if you would like to show students which questions they missed or not, the correct answers, and the point values.