Topics include PDF/A-2 at the PDF/A Conference and the Council Directive 2010/45/EU, which demands equal treatment for electronic and paper invoices. An electronic invoice should be readable from the point in time of its issue until the end of its storage period. The use of PDF/A as a storage format for electronic invoices guarantees their reproducibility in all technological contexts longer than legally required: the format characteristics guarantee conformity with the original in all environments and assures the legibility of documents longer than the minimum storage period in Italy of 10 years. The advanced electronic signatures that can be affixed to every PDF/A document completely satisfy the requirement to assure the authenticity and content integrity. This process assures that the document was really originated from his sender and that it wasnt modified since its issue.