A keypad is a set of keys or buttons arranged in a specific layout, used for inputting data or commands into electronic devices. Commonly found on devices like telephones, computers, and security systems, keypads can be mechanical or touch-sensitive. They often feature numbers, letters, and symbols, allowing users to enter information easily. Keypads come in various forms, including numeric keypads, which typically have 0-9 and additional function keys, and alphanumeric keypads, which include letters as well. They are essential for tasks such as dialing phone numbers, entering passwords, or controlling devices like microwave ovens and ATM machines.