UI stands for User Interface, and it’s all the stuff you see and click on when you use an app or website—like buttons, menus, forms, icons, and so on. It’s how you interact with the system. The whole point of UI design is to make using the site or app easier and more fun. A good UI should be clean, attractive, and super easy to use, so people don’t get confused and can do what they came for. The better the UI is, the more likely it is that people will enjoy using the product and keep coming back.