Our country's law does not stipulate that the loan must be in duplicate. Generally, only one IOU is needed, that is, the creditor can hold it, but it is ok if the actor wants to write two IOUs. In addition to clear handwriting and complete paper, the IOU itself must also indicate the debt reason, debtor's name, amount owed and currency. If there is interest, the calculation method of interest should also be indicated. If a large loan needs to be secured, the guarantor shall be required to sign and seal it, and it will take effect after the debtor signs and seals it.

(a) white writing should pay attention to the following matters:

1, IOUs are evidence of the relationship between creditor's rights and debts, so don't scribble when writing IOUs, and keep IOUs well to prevent them from being lost.

2. The IOUs must be legible and cannot be altered. In case of change, the changing party shall affix its official seal or signature at the change place.

3. The amount of money on the IOUs should include both uppercase and lowercase as far as possible. People's Republic of China (PRC) Civil Code

Article 667 A loan contract is a contract in which the borrower borrows money from the lender, repays the loan at maturity and pays interest.

Article 668 A loan contract shall be in written form, unless otherwise agreed between natural persons.

The contents of a loan contract generally include terms such as loan type, currency, purpose, amount, interest rate, term and repayment method.

Article 669 When concluding a loan contract, the borrower shall, at the request of the lender, provide the true information about the business activities and financial status related to the loan.