Once you have created your quiz, and the students submit that to you, you have two options for grading. If you created a multiple choice quiz, and chose to have Google to immediately release your grade to the student, they will immediately see the grade he/she earned. They can go into the personalized feedback that you have provided and allow additional learning opportunities to take place. However, your work is not complete. You still have to go into Google Classroom, if you are using that as an option to deliver your quiz, and release the grade to the students.