1. IOUs without fingerprints are valid. 1. IOUs without fingerprints can be valid. The IOU is not fingerprinted, but it is valid if it is signed by the debtor. 2. The law stipulates that IOUs should be in written form. The contents of IOUs generally include terms such as the type of debt, currency, purpose, amount, interest rate, term, and repayment method. Therefore, an IOU is valid as long as it has the above-mentioned content and has the autograph of the debtor. 3. Legal basis: Article 667 of the "People's Republic of China and Civil Code" stipulates that a loan contract is a contract in which the borrower borrows money from the lender, returns the loan and pays interest when due. Article 668 stipulates that a loan contract shall be in writing, 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.

2. Is the prenuptial agreement valid if it is only signed but not fingerprinted? A prenuptial agreement that is only signed but not fingerprinted will be valid as long as it meets other validity conditions. According to the legal provisions of the Civil Code, if an agreement in written form does not violate legal provisions and reflects the true intentions of both parties to the agreement, the contract will be established and effective when both parties sign, seal or fingerprint. Except as otherwise provided by law or otherwise agreed upon by the parties.