A keypad is a set of buttons arranged in a grid, used for inputting data or commands into electronic devices. Commonly found on devices like telephones, calculators, and keyboards, keypads can vary in size and layout. They typically feature numbers, letters, and function keys, allowing users to perform various tasks. Keypads can be mechanical or touch-sensitive, depending on the device. They are essential for user interaction, enabling functions such as dialing phone numbers, entering passwords, or controlling appliances. Some keypads are designed for specific applications, like ATM machines or security systems, enhancing their usability in various contexts.