You may find that some of your students need additional time or attempts to take a Canvas quiz. Fortunately, you can use the built-in quiz moderation tools to handle these accommodations. On the Moderate Quiz page, you can manually unlock (and re-lock) a quiz for a specific student, allow more time to complete a timed quiz, and/or grant an additional attempt at taking a quiz. Once a quiz is published, you can access the Moderate Quiz page that is linked to that specific quiz.
The Canvas Instructor Guide has an introductory guide to the Moderate Quiz page and the tools available there. The Instructor Guide also has detailed instructions on giving students extra time and on giving students extra attempts to take a quiz.