Maybe a student needs to take an online quiz again. This tutorial will help you with granting one or more attempts in Canvas New Quizzes.
Quiz Build Page
Click on the link for one of the New Quizzes.
At the bottom click on the Build button.
On the top click on the Moderate tab.
On the row with the student you want to grant accommodations to, click on the Moderate button.
On the right-hand side a menu will appear. There will be a selection Additional Attempts. Here you will want to add the number of additional attempts you want to grant the student.