In the first part of this article we first in the definition of what a digital certificate, how it relates to electronic signatures and explain the role that institutions entitled to issue digital certificates, the Certification Authorities. In this second part we will focus on how to develop the digital certificate and invoices certified scanning are complementary. The digital certificate and invoices certified scanning The need to manage the high number invoices and receipts associated with the business of a company, means bear the costs associated with printing, shipping and handling of the document, which results in an expenditure of approximately 1.2 euros per invoice sent and even more per invoice received, especially by the obligations of custody. With the entry into force of Royal Decree 1496/2003 of 28 November, approving the regulation which governs the billing obligations, encourages the possibility to transmit invoices electronically, allowing a saving of significant costs. Similarly, following the publication of the EHA Order 962/2007 of 10 April it is possible to destroy the invoices received on paper if you have previously made a digitization process gets certified digital copies signed electronically through an approved scanning software . The standard EHA/962/2007 of April 10, 2007 Digitization is defined as the process by which, using photoelectric or scanning techniques, it becomes an image contained in a paper document into a digital image encoded. Through the digitization certified invoices are kept in electronic format with full tax and legal validity, so that the original paper can be removed permanently. .