A pendulum clock with punch cards
These days most businesses use a software which stores and records the click of a button at a specific time.
In recent years, a time clock would have been an automated system using swipe cards, badges, or biometric data like fingerprints to record time in and out from work.
Long ago – and some of us even remember the days – a time clock was a large machine that stamped the time in and the time out on thick paper cards.