The purpose of a user interface (UI) in product design is to facilitate user interaction with a product or service effectively and intuitively. A well-designed UI aims to create a seamless experience by employing visual elements such as buttons, menus, and icons, enabling users to perform desired actions with ease. It encompasses aspects of usability and aesthetic appeal, ensuring that the interface is not only functional but also engaging. In essence, UI design is critical for enhancing user satisfaction and achieving business objectives.