Legal analysis: IOUs without ID cards are also valid. As long as the IOU has the name of the creditor, the amount of the loan, the name of the debtor and the date of the loan, it has legal effect.

Legal basis: Article 668 of the Civil Law of People's Republic of China (PRC) 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.