First of all, the legal full names of borrowers and lenders should be clearly written.

1. In practice, lenders and borrowers are often closely related, not universally related. When borrowing money, they write the title of their daily habits as IOUs. In case the borrower fails to repay the loan in time, the lender will often be rejected by the court because of unclear creditor's rights and debts.

Two, should write clearly the loan amount, including the amount expressed in words and figures.

1. The loan term should be clearly written, including the start and end dates of the loan and a clear loan term;

Third, the specific repayment date should be clearly written.

1. Loans within the limitation of action are protected by law, but in practice, many lenders often don't know the concept of "limitation of action". There are different understandings about the limitation of action when there is no agreed repayment period for the loan. Some people advocate the application of two-year statute of limitations, while others advocate the application of 20-year statute of limitations. Courts in different places have different understandings of this issue.

2. Therefore, from the perspective of safe recovery of creditor's rights, the repayment period should be written into the IOU when borrowing. If the borrower fails to repay the loan within the time limit, the lender shall claim rights within two years after the repayment due date, including bringing a lawsuit to the people's court or the borrower signing a dunning notice for confirmation. The loan interest should be clearly written, with a clear annual interest rate or monthly interest rate, and the total amount of loan interest that should be paid at last (including the amount expressed in words and figures).

Four, the date, month, day, time and payment method of repayment of loan principal and interest should be stated.

Many creditors misunderstand that private lending can't charge interest, so interest is only an oral agreement and is not written into the loan. If the interest rate is not written into the IOU, the lender will not get the support of the court once it sues the borrower for not recognizing the agreement between the two parties. In fact, the law stipulates that private borrowers can agree on interest within 4 times of the bank's loan interest rate for the same period.