Legal analysis: 1. As long as the IOU expresses the true intention of the parties and has legal content and is confirmed by the signature of the party, it is legally valid and does not require fingerprinting; 2. Even if the IOU is signed by the party, Defects in the form will not affect the court's hearing of the case. 3. The court will determine whether a loan relationship exists based on the "IOU" or "receipt" with a defective form, combined with other evidence. At the same time, for loans delivered in cash, the court can determine whether there is a loan relationship based on The delivery certificate, payment ability, transaction habits, the size of the loan amount, the relationship between the parties, and the transaction details stated by the parties are comprehensively used to determine whether there is a legal and true creditor-debt relationship between the two parties.

Legal basis: "The People's Republic of China and the Civil Code"

Article 667 A loan contract means that the borrower borrows money from the lender and returns the loan and pays it when due interest contract.

Article 668: A loan contract shall be in written form, unless otherwise agreed upon for a loan between natural persons. The content of a loan contract generally includes terms such as loan type, currency, purpose, amount, interest rate, term and repayment method.