Fernando Resina de Silva and Conceição Gamito, partner responsible for the IT department and senior lawyer in the Tax department respectively, formed a work group to prepare a study of “the Electronic Invoice, an instrument of the Information Society”, put together as an initiative of the Association for the Promotion of the Information Society. On 8th October APDSI laid on a presentation of the course, in which the concept of electronic invoicing was tackled, as well as the conditions and advantages of its use and a number of general recommendations related to the phenomenon.