Tax-free. The tax-exempt invoices are the invoices issued by the units enjoying VAT tax exemption, specifically the sales invoices issued by the agricultural producers selling tax-exempt agricultural products and the purchase invoices issued by the units acquiring tax-exempt agricultural products.2022 Harbin epidemic during the invoices tax exemptions. Harbin City, referred to as "Ha", also known as the city of ice, the ancient name of the capital, Huiningfu, Alle Kam, Binjiang, is the capital of Heilongjiang Province, a sub-provincial city, the core city of Harbin metropolitan circle.