Web Content Accessibility Guidelines (WCAG) are organized under four principles:
Perceivable-
Operable- allows learners to navigate the information independently using their preferred devices.
Understandable - use a consistent and predictable design.
Robust -compatible with operating systems, browsers, and current technologies, including assistive technologies.
Source: Designing for Accessibility with POUR by the National Center on Accessible Educational Materials is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Source: Understanding the 4 Principles of Accessibility from Indiana University Bloomington by Matt Fitzwater.