See it all the time in movies. An official deed or contract is presented and held as law. Particularly from England to the Americas during 1600’s to 1700’s. Someone brings me a contract and I don’t like it. I tear it up. Who holds the contract accountable without a piece of paper?
If I understand the question, this is an old problem, and had old solutions.
You were a tenant farmer in 1578 in Kent and had paid your rent to your landlord. You wanted a receipt, but couldn't read. Solution- a tally stick. Your name was written on a hazel stick ( typically), notches were cut into it signifying the amount paid. Then it was split down the middle- half to you, half to your landlord. If there was a question about the amount later, the two halves could be matched up.
The same thing could be done with paper. The contract was written twice on one piece of paper, then the paper cut jaggedly between the two copies. If there was a question about the amounts, the agreements etc., the two pieces could be re-assembled. Your landlord could tear up his own copy- but not yours, and if he tore up his own yours would stand in court. If you feared he could take yours by force, there could be three copies made on the same piece of paper, and one copy filed in court- so, if your landlord was able to take away your copy, he'd still have to deal with the one on file there.
By the way, that jagged cut between the two copies looked toothy, therefore these agreements were commonly called indentures- the same root as dentist, dental, etc. So, yes, an indentured servant would have one toothy half of her contract to serve a master for a given time, her master the other.