A doctor appointment app UI design should be clean, user-friendly, and intuitive. The app should aim to simplify the process of booking an appointment with a doctor or medical professional, and should have a straightforward navigation system that allows users to easily access the information they need.

The app's home screen should prominently display the user's upcoming appointments and provide easy access to their medical history, prescription information, and any other important medical documents. The user should also be able to search for doctors and medical facilities based on their location, specialty, and availability.