legal ground
Article 4 of the Provisions on the Use of Special VAT Invoices consists of basic invoices or basic invoices plus other invoices. Basic linkage and triple linkage: invoice linkage, deduction linkage and bookkeeping linkage. A copy of the invoice as the accounting voucher for the buyer to calculate the purchase cost and VAT input tax; Deduction form, as the certificate submitted by the buyer to the competent tax authorities for certification and kept for future reference; The accounting voucher is used as the accounting voucher for the seller to calculate the sales income and VAT output tax. Other common purposes are determined by ordinary taxpayers.
skill
The above answer is only for the current information combined with my understanding of the law, please refer carefully!
If you still have questions about this issue, I suggest you sort out relevant information and communicate with professionals in detail.