walking papers / ticket

What is the origin of the idiom "walking papers" and when to use it?

The origin of the idiom "walking papers" is unclear, but it is believed to have originated in the United States in the early 20th century. It is thought to refer to the practice of giving someone a written notice of termination and then allowing them to leave the workplace immediately. This idiomatic expression is used to describe a situation where someone is fired or dismissed from their job.