According to the provisions of my country's Contract Law, the IOU can be printed and then signed by the borrower, but the content of the IOU must be complete and must include the loan amount, repayment period, loan interest, etc. Relevant legal provisions: "Contract Law of the People's Republic of China" Article 196 A loan contract is a contract in which the borrower borrows money from the lender and returns the loan and pays interest when due. Article 197 The loan contract shall be in written form, unless otherwise agreed on the loan between natural persons. The content of the loan contract includes terms such as loan type, currency, purpose, amount, interest rate, term and repayment method. Article 198 When entering into a loan contract, the lender may require the borrower to provide a guarantee. The guarantee shall be in accordance with the provisions of the Guarantee Law of the People's Republic of China. When writing an IOU, the IOU should include the identity information of the borrower and the lender; the loan amount, loan interest, repayment term, loan time, liability for breach of contract, etc. Article 490 of the "People's Republic of China and Civil Code" If the parties conclude a contract in the form of a contract, the contract shall be established when both parties sign, seal or fingerprint. Before signing, sealing or fingerprinting, one party has performed its main obligations and the contract is established when the other party accepts it. Laws and administrative regulations stipulate or the parties agree that a contract should be concluded in written form. If the parties do not use written form but one party has performed its main obligations and the other party accepts it, the contract is established. Article 668 of the "People's Liberation Army and Civil Code" of the People's Republic of China shall be in written form, unless otherwise agreed on the 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. Article 143 of the "People's Republic of China and Civil Code" is valid for civil legal acts that meet the following conditions: (1) The actor has the corresponding capacity for civil conduct; (2) The expression of intention is true; (3) It does not violate The mandatory provisions of laws and administrative regulations do not violate public order and good customs.