A Web UI, or Web User Interface, is the part of a website or web application that users interact with. It includes elements like buttons, menus, and forms that allow users to navigate and perform tasks online. A well-designed Web UI enhances user experience by making it easy to find information and complete actions. Web UIs are built using technologies such as HTML, CSS, and JavaScript. These technologies work together to create visually appealing and functional interfaces. Designers and developers focus on usability and accessibility to ensure that all users, including those with disabilities, can effectively use the web application.