Accessibility refers to design that includes or involves everyone and also take into recognition the people living with disability.
As a UI UX designer, I ensure that all my designs are accessible and straight to the point. To achieve this, I make use of the accessibility guidelines like contrast checker and WCAG 2.1 . This involves designing for users that might have a range of disabilities, including visual, auditory, physical, speech, cognitive, language etc.
Overall designing for accessibility helps to create a positive user experience for all users.