Legal analysis: If you sign an IOU but don't show your identity, there is evidence to infer your identity, so the impact is not great. An IOU usually contains three identities: borrower, lender and guarantor, and its legal responsibilities are also quite different. If identity cannot be inferred, the rights and obligations of all parties may be affected.

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

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.