Core Viewpoint - The article discusses the importance of tax deduction vouchers for enterprises when calculating taxable income for corporate income tax, categorizing them into internal and external vouchers [5][6]. Group 1: Tax Deduction Vouchers - Tax deduction vouchers are essential for enterprises to substantiate expenses related to income generation and are classified into internal and external vouchers [5][6]. - Internal vouchers are self-made accounting documents used for recording costs, expenses, losses, and other expenditures, such as payroll sheets and cost allocation forms [5]. - External vouchers are obtained from other entities or individuals during business activities, serving as proof of incurred expenses, including invoices, tax payment certificates, and receipts [5]. Group 2: Policy Basis - The article references the National Taxation Administration's announcement regarding the management of tax deduction vouchers, which outlines the definitions and requirements for both internal and external vouchers [5][6]. - It emphasizes that the preparation and use of internal vouchers must comply with national accounting laws and regulations [5].