Chongqing tax invoices can be purchased at the invoice sales window of the local competent local tax authority. All taxpayers who pay business tax should go to the invoice sales window of the local competent local tax authority after completing tax registration, obtain an invoice purchase book, and purchase invoices according to business items. Taxpayers who purchase invoices again need to go to the invoice sales window based on the invoice stub they purchased last time to verify the old one and purchase the new one.