User Interface (UI) refers to the visual and interactive elements through which users interact with software applications, websites, or devices—screens, buttons, menus, forms, and other controls. Good UI design makes systems intuitive, easy to navigate, and accessible to users with varying abilities and technical comfort. UI design considers visual hierarchy, consistency, feedback, and error handling. Government digital services require thoughtful UI design to ensure citizens can access services regardless of technical sophistication. Accessibility requirements (WCAG standards) affect UI design, ensuring compatibility with screen readers and other assistive technologies. UI design works alongside UX (User Experience) design, which focuses on overall user journey and satisfaction. Modern UI design emphasizes mobile-friendly responsive layouts.