A Loan Agreement is an agreement between a lender and a borrower detailing the terms and conditions of the loan. A friendly loan agreement is usually made between friends, family or acquaintances. In most friendly loan agreements and depending on the relationship and agreement between the parties, interest is not applicable nor is there a requirement for security or guarantee.
This is a standard loan agreement to be used in case of a friendly loan. The Agreement provides a good guide and has explanatory notes on what to do when you are acting for a lender or a borrower.