Group 1 - The article emphasizes that invoices must be filled out completely and accurately, including the full name of the payer, to be valid for reimbursement [2] - Invoices without a taxpayer identification number or credit code cannot be used for reimbursement if the buyer is a business, as per regulations effective from July 1, 2017 [3] - It is not permissible to change the item name on an invoice as requested by the customer; the item name must reflect the actual goods or services provided [4] Group 2 - Invoices that do not match the actual transaction details are considered problematic; all invoices must be issued truthfully and in accordance with regulations [5]