Power door lock actuators are usually thought of as a device on a car. While this is the most common usage, there are other types of actuators.
Power door lock actuators on a car are operated by using either a key or a keypad system of numbers as a code. Many cars come with those already equipped, but they can be installed aftermarket.
Many people also now have power door lock actuators on the doors of their homes as a safety measure. They are usually operated by a numeric keypad that looks much like a telephone keypad.