WCAG 2.1 Compliance
WCAG means Web Content Accessibility Guidelines. They are the most essential guidelines for web accessibility policy and set the standard for web accessibility legislation in the majority of countries around the world.
4 Principles of WCAG 2.1
Information and user interface components must be presentable to users in ways they can perceive.
User interface components and navigation must be operable.
Information and the operation of user interface must be understandable.
Content must be robust enough that it can be interpreted by by a wide variety of user agents, including assistive technologies.