An Agreement Letter for Borrowing Money is a contract between two parties, where the borrower agrees to borrow money from the lender in exchange for the promise of paying it back at an agreed-upon rate and repayment period. This document should include all of the details of the loan agreement, including the amount being borrowed, the payment schedule, the interest rate, and any late fees or other penalties if payments are not made on time. It also serves as a written record of mutual understanding between both parties, and should be reviewed carefully before signing.