User input refers to the information or commands that a user provides to a computer or software application. This can include typing text, clicking buttons, or using touch gestures on a screen. User input is essential for interactive systems, as it allows users to communicate their needs and preferences to the software. In many applications, user input is processed to perform specific tasks or generate responses. For example, in a search engine like Google, user input helps retrieve relevant information based on the keywords entered. Proper handling of user input is crucial for ensuring a smooth and effective user experience in software design.