There are 3 cases to define: + In case of purchase of goods from a flat-tax paying unit such as an individual business household, it is necessary to fully comply with regulations on accounting documents, accounting entries and exclusions on the year-end corporate income tax declaration. Enterprises are not penalized for invoices in this case. + In case of purchasing agricultural, forestry and fishery products, soil, rock, sand, gravel, etc., in the case where there is no invoice but must make a list according to the provisions of law, the list must be made according to the provisions of law. If the enterprise does not make a legal list, the enterprise shall not be included in the purchase cost of these goods. + In case of purchase without an invoice: Not included in the cost, if included, it will be excluded from tax finalization and sanctioned for tax administrative violations.