It is best to plan, design, develop, test and review content with users with a broad range of physical and cognitive abilities.
The next option is to involve an accessibility consultant. It’s not recommended to rely on accessibility overlays built into software.
WAVE Web Accessibility Evaluation ToolWebAIM colour contrast checker
AbilityNet: Digital Accessibility ResourcesWebAIM: Quick reference accessibility principlesGDS: Design system components – passed WCAG 2.1 requirementsContent Design London: Readability Guidelines wiki