What is User Interface (UI) Design?

Simply stated, "UI refers to how people interact with computers, machines, websites, apps, wearables, and other programs or devices. User interface design is the process of making these things as easy to use and efficient as possible."

Whereas UX (User Experience) refers to the journey through an application or process where designers focus on the overall form and function, UI (User Interface) focuses on how a product’s surfaces look and function. Thus, UI designers work with the tangible and visible elements of the process.