A user interface (UI) is a point of interaction between a human and a computer system, crucial for user experience in software applications. Its design encompasses both visual elements, like buttons and menus, and interaction methods, such as touch or voice controls. An effective UI reduces the learning curve, enhances usability, and increases user satisfaction. Its importance grows as technology becomes more integrated into daily life, emphasizing the need for intuitive, accessible, and efficient interfaces to facilitate interactions with complex systems.