Letting Students Take Exams/Quizzes at Different Times
If your student is taking an exam at a different time than the rest of the class (because they’re working with the Office of Disability Services, were sick, etc.) you can change that in the “Assign To…” window.

From there, you can add a new assignment for the student in question. Just click the “Add” button, and then you can specify a new time for their exam to start.

Setting Extra Time for a Student
If you set a time limit for an exam, and a student has an exam time extension accommodation, you can extend their time in the moderation tools. You can access these tools by clicking “Moderate this Quiz” for classic quizzes after the quiz has been published:

Or, by opening the moderate menu while building a new quiz:

When in the moderate window, just select the student and press the pencil icon to edit:

From there, you can add extra time to match the accommodation in the student’s letter. Please note, if you’ve set your exam to only be available for a limited time, you may also need to change the time it’s available by using the "Assign to...” window.