User interface is the graphical layout of a system that allows users to interact with it.

User interface (UI) in product management is the way a user interacts with a product. It includes the design of the product’s graphical user interface (GUI), as well as the user experience (UX) of using the product. UI is an important part of product management because it helps to ensure that users can easily and effectively interact with a product. UI design involves creating an intuitive, visually appealing, and easy-to-use interface that allows users to quickly and easily access features and functions. This includes designing menus, buttons, icons, and other elements that make up the user interface. Additionally, UI design also involves creating a consistent look and feel across all platforms so that users have a consistent experience regardless of which device they are using. Finally, UI design also involves testing to ensure that the interface works properly on different devices and operating systems.

1. Graphical User Interface (GUI): This is a type of user interface that allows users to interact with electronic devices through graphical icons and visual indicators such as secondary notation, instead of text-based user interfaces, typed command labels or text navigation. Examples of GUI include the Windows operating system, Apple's macOS and iOS, and Google's Android operating system. 2. Command Line Interface (CLI): This is a type of user interface that allows users to interact with a computer program by typing commands into a terminal window. Examples of CLI include the Unix shell, the MS-DOS command prompt, and the PowerShell command line interface. 3. Voice User Interface (VUI): This is a type of user interface that allows users to interact with electronic devices using voice commands instead of typing or clicking on graphical elements. Examples of VUI include Amazon Alexa, Apple's Siri, and Google Assistant.