A Mobile User Interface (UI) refers to the design and layout of applications and features on mobile devices, such as smartphones and tablets. It focuses on how users interact with their devices through touchscreens, buttons, and gestures. A well-designed mobile UI enhances user experience by making navigation intuitive and visually appealing. Key elements of a mobile UI include icons, menus, and buttons, which are optimized for smaller screens. Designers often use frameworks like Material Design or iOS Human Interface Guidelines to create consistent and user-friendly interfaces. Effective mobile UIs prioritize accessibility and responsiveness to accommodate various user needs and device sizes.