The contents of the IOU need to clearly indicate the borrower, the borrowing time, the borrowing amount, the payment delivery and the guarantee. The borrower needs to write his name and ID number clearly, and the date of borrowing should be accurate to the day. The repayment date can be agreed in the IOU. If there is no agreed repayment date, the borrower can claim repayment at any time. If the repayment date is agreed, the repayment can only be requested after the repayment date expires. If the repayment date is not returned, the lender shall bring a lawsuit within three years. Failure to file a lawsuit within the time limit will lose the right to win the case. In addition, the loan amount should be clearly written in uppercase and lowercase letters, and the currency should also be clearly written. Payment should be made by bank transfer as far as possible, and the account number and transfer date of the other party should be clearly defined in the receipt.