Legal analysis: The writing format of IOUs is as follows: 1. The title of the title debt note generally consists of the name of the language, that is, the word debt note is written in a larger font at the top and middle of the text; 2. The text of the IOU should write how much is owed by who or what unit, and indicate the repayment date; 3. The name of the owed party and the autograph of the agent shall be signed by the department. If the IOU is issued by an individual, the department shall sign the name of the IOU. Meanwhile, the date of signing the debt. Units should build official seals and individuals should build private seals; 4. Precautions for writing IOUs IOUs are to pay back money or ask for the credentials of IOUs, so don't scribble when writing IOUs.

Legal basis: Paragraph 1 of Article 2 of the Provisions of the Supreme People's Court on Several Issues Concerning the Application of Laws in the Trial of Private Lending Cases. When the lender brings a lawsuit to the people's court, it shall provide debt certificates such as IOUs, receipts and IOUs, as well as other evidence that can prove the existence of the legal relationship between lending and borrowing;

(2) If the creditor's rights certificates such as IOUs, receipts and IOUs held by the parties do not specify the creditor, and the party holding the creditor's rights certificate brings a private lending lawsuit, the people's court shall accept it. The defendant raised a factual defense against the plaintiff's creditor qualification. If the people's court considers that the plaintiff is not qualified as a creditor after trial, it shall rule to dismiss the prosecution.