A computer interface is a point of interaction between a user and a computer system. It allows users to communicate with the computer, input data, and receive output. Common types of interfaces include graphical user interfaces (GUIs), which use visual elements like icons and buttons, and command-line interfaces (CLIs), which require text-based commands. Interfaces can also refer to how different systems or devices connect and communicate with each other. For example, the USB interface allows various devices, such as printers and external drives, to connect to a computer. Effective interfaces enhance user experience and improve productivity.