The keyboard is the primary device used to input information into a computer system. It consists of a set of keys representing letters, numbers, symbols, and other functions. When a key is pressed, it sends a signal to the computer, which then processes and displays the corresponding character or action on the screen. The keyboard allows users to interact with the computer by typing text, entering commands, and navigating through various applications and menus. It is an essential tool for data entry, communication, and overall computer usage.