An agreement letter for payment between two parties is a document that outlines the terms of a financial transaction between two individuals or entities. It should include details such as the amount of money to be exchanged, when and how payments will be made, any applicable late fees or interest rates, and any other details that are relevant to fulfilling the agreement. Together, both parties should read, sign and date the agreement letter for payment, making sure that all details are correct and agreed upon before it goes into effect. Having a written document outlining the understanding between two parties can help reduce the chances of confusion in the future and ensure that each party is held accountable for their obligations.