Various state and federal laws have requirements aimed at making education accessible to as many people as possible. For instance, making sure that classrooms are wheelchair accessible would be an effort to comply with these laws and policies. Online classes need to be accessible as well. This document outlines some general best practices when designing a course for accessibility concerns. Additional help can be found at Creating Accessible Electronic Content.
Specific Canvas-related accessibility help can found in the Accessibility within Canvas document. If you have additional suggestions, please contact accessibility@instructure.com.