Is it illegal for a lawyer to charge agency fees without issuing an invoice? It is illegal for a lawyer to charge agency fees without issuing an invoice. According to the provisions of the Lawyers Law on lawyer practice disciplines, lawyers must issue invoices after collecting fees to ensure the legality of the transaction and tax compliance. Issuing invoices is not only a requirement of lawyers’ professional ethics and standards, but also a basic requirement to comply with fiscal and taxation laws and regulations. Failure to issue an invoice is illegal.