Legal analysis: the use scope of special invoice is limited to invoices, and it has no legal effect to affix the special invoice seal on documents other than invoices.

Legal basis: Measures for the Administration of Invoices in People's Republic of China (PRC).

Article 10 Invoices shall be overprinted with a unified national invoice producer seal. The style of the national unified invoice producer seal and the requirements for invoice layout printing shall be stipulated by the competent tax department of the State Council. The invoice producer seal shall be made by the tax authorities of provinces, autonomous regions and municipalities directly under the Central Government. It is forbidden to forge the seal of invoice producer.

Invoices should be changed irregularly.

Article 11 An enterprise that prints invoices shall, in accordance with the unified provisions of the tax authorities, establish an invoice printing management system and storage methods.

The use and management of invoice producer seal and invoice anti-counterfeiting special products shall be subject to the system of special person in charge.

Article 12 An enterprise that prints invoices must print invoices in the style and quantity approved by the tax authorities.