For an IOU to be legally effective, the first thing that must be met is that the content written on the IOU must comply with legal regulations, then the format of the IOU must meet the requirements, and then the IOU must be signed by the debtor.

When writing an IOU, you should pay attention to the following points:

1. The IOU should state who is the debtor, who is the creditor, and what kind of debt disputes exist between the creditor and the debtor. The specific content must be stated clearly, and there should be no ambiguous words in the IOU. For example, "return" cannot appear in the IOU.

2. Pay attention to writing IOUs. If you need to write a name, the name should be based on the name on the other person's ID card, and all other information should be based on the information on his ID card. If the creditor or debtor involves an entity, the IOU should also be stamped with the company's official seal.

3. The amount appearing on the white slip must be written clearly, using both numbers and traditional Chinese characters. If it involves proportions, write them clearly, such as percentages, thousandths, etc.

4. The content of the IOU must be clearly expressed without ambiguity. The specific date and time must be written clearly, and whether interest must be paid. If you want to pay interest, you must write it clearly on the IOU, otherwise it will be treated as non-payment of interest. If a guarantor is involved, some relevant information about the guarantor must also be written clearly in the IOU, so as to ensure the authenticity and reliability of the guarantee.

5. Two copies of the same IOU are required, one each for the debtor and the creditor. Whether the IOU has legal effect depends on whether the other party voluntarily signed the IOU; whether the specific amount is clearly written on the IOU; and the person who writes the IOU needs to have civil capacity; if it is written by a mentally ill person, it will generally be regarded as having no legal effect. IOU. Therefore, the issues that should be considered or paid attention to when writing an IOU must be clearly stated to avoid unnecessary trouble later.