According to legal provisions: 1. The expression of intention must be true and clear, and the borrower can sign or fingerprint for confirmation. The law does not require fingerprinting. 2. Standard writing of the IOU should do the following: 1. The borrower should handwrite the full text of the IOU and sign it, do not print it; 2. The content of the IOU should be stated accurately and avoid ambiguity; 3. The loan time and purpose of the loan should be written clearly (the purpose should be It is legal and cannot be used for illegal purposes such as gambling), interest agreement, and repayment period; 4. When the lender pays the money, try not to pay it in cash, especially for large loans, it must be done through bank transfer, and the other party’s account must be The name is the same as that of the borrower; 5. If the other party has poor credit or repayment ability, a guarantee or guarantor may be required. Note: The borrower refers to the debtor, the person who needs to borrow money, and the lender refers to the creditor, the person who provides loans or lends money to others. If both parties need to agree on many matters, they can sign a loan contract and make detailed arrangements while writing the IOU. The above is the answer to whether fingerprints are required for IOUs.