“Often designers use color as a method to identify if a form control is required. When a user moves into the form field or moves out of the form field, the form control changes to a red color. This method is not recommended as it is not accessible for users with low vision, colorblind users, users with cognitive disabilities, and users with visual disabilities. This method can be implemented if there is an alternative fallback method that is “a visual cue,” which can help all users identify if the form control is a required field.”
People with disabilities (temporary or permanent) feel and *are* less disabled if things work for them.
This is a very good article – also for UX Designers: The Anatomy of Accessible Forms: Required Form Fields https://www.deque.com/blog/anatomy-of-accessible-forms-required-form-fields/