What is an autopen and can you tell if one has been used?

As a machine replicating a person, there's some apprehension toward autopens. Is it possible to tell if it has been used in ...
Poynter

Trump has no power to undo Biden’s autopen pardons

President Donald Trump has repeatedly said former President Joe Biden signed pardons with an autopen, a mechanical device that uses a robotic arm with an attached pen. When Trump installed portraits ...