According to the provisions of the Chinese Civil Code:

1. All IOUs can be printed or handwritten.

2. Whether it is handwritten or printed, the signature must be handwritten, otherwise the authenticity of the borrower cannot be proved.

3. The printed IOU shall at least have the following basic contents: the name information of the borrower and the borrower, the loan amount, the loan term, the interest, the liability for breach of contract, the borrower's signature and the date of signature.

Legal basis:

Article 668 of the Civil Code of People's Republic of China (PRC) stipulates that 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.