A keyboard is an essential input device for computers, allowing users to enter text and commands. It consists of keys that represent letters, numbers, and special characters. Each key has a specific function, such as typing letters, executing commands, or controlling the computer's operations. Function keys, often labeled F1 to F12, provide quick access to various features and shortcuts. For example, F1 typically opens help menus, while F5 is commonly used to refresh a webpage. Additionally, modifier keys like Shift, Ctrl, and Alt enhance the keyboard's capabilities, enabling users to perform multiple actions with a single keypress.