A loan agreement is a legal document between a creditor who lends money to a borrower that is repaid with interest. An IOU (I Owe You) is a legal document that sets out the details of a loan made between two people, a borrower, and a lender.Use our free Loan Agreement template to create a contract online. This free sample demand letter to pay is for a personal loan to an exroommate. Remember, this is only an example of a demand to pay. A demand letter is an official notice requesting money, possession of assets, or action on a legal matter. B. Loan Repayment Terms. Filling out the California Promissory Note form requires attention to detail. No matter the protective measures taken, it is a simple market fact that borrowers default on loan terms or payments.