The signatures to a contract must be subscribed, that is, they must be placed at the bottom of the contract and are usually placed at the lower right hand side. In case a person cannot write, his mark will be sufficient, provided it is witnessed by a third person and his name is written near it in the customary way and by a duly authorized party. One party to a contract cannot write, "by mark" the name of the other party to the contract.

When an agent signs a contract, the plumber should make sure that he signs it for - and so as to bind, his principal. To do so, he would have to sign:

"August Blank" "by Albert Factor, Agent." If he were to write his signature:

Albert Factor, agent for August Blank" the contract would not be binding on August Blank, for the agent has signed the agreement with his own name, the clause "Agent for August Blank" merely serving in the eyes of the law as a means of identifying or explaining what Albert Factor is party to the contract.