Legal analysis: for other documents or vouchers that have not signed a formal sales contract but have the effect of replacing the contract, the relationship between supply and demand of both parties can be clarified. The settlement of supply is contractual in nature, and stamp duty should also be paid according to regulations. If the "purchase order" in the system is a taxable voucher signed in electronic form, it shall be stamped as required.

Article 2 of the Provisional Regulations on Stamp Duty stipulates that the following documents are taxable documents: purchase and sale contracts, processing contracts, construction project contracts, property leasing, cargo transportation, warehousing, loans, property insurance, technology contracts or documents of a contractual nature.

Legal basis: Paragraph 2 of Article 4 of the Detailed Rules for the Implementation of the Provisional Regulations on Stamp Duty in People's Republic of China (PRC) refers to agreements, contracts, contracts, documents, confirmations and other documents of various names.

People's Republic of China (PRC) tax collection management law

Article 1 This Law is formulated with a view to strengthening the administration of tax collection, standardizing tax collection, safeguarding national tax revenue, protecting the legitimate rights and interests of taxpayers and promoting economic and social development.

Article 2 This Law is applicable to the collection and management of various taxes collected by tax authorities according to law.

Article 3 The collection, suspension, reduction, exemption, refund and supplementary payment of taxes shall be carried out in accordance with the law. Where the State Council is authorized by law, it shall be implemented in accordance with the administrative regulations formulated by the State Council.

No organ, unit or individual may, in violation of the provisions of laws and administrative regulations, arbitrarily make decisions on tax collection, suspension, tax reduction, exemption, tax refund, overdue tax and other decisions inconsistent with tax laws and administrative regulations.

Article 4 Units and individuals that are obligated to pay taxes according to laws and administrative regulations are taxpayers.

Units and individuals that have the obligation to withhold and pay taxes according to laws and administrative regulations are withholding agents. Taxpayers and withholding agents must pay taxes, withhold and remit taxes and collect and remit taxes in accordance with the provisions of laws and administrative regulations.