How To Write An Agreement Letter Between Two Parties . Sign the letter and print your name below. How to write an agreement letter between two parties. 9+ Contract Agreement Letter Examples PDF Examples from www.examples.com Some states don't require witnesses for an agreement to be legally enforceable, but an agreement claimed. This information explains the obligations that both parties have agreed under the agreement. As per our agreement, i will pay you ___ (mention the amount) advance payment before your joining.