Invoicing in an electronic environment ensures a fast and efficient flow of data interchange, which is crucial for organising processes in both the private and the public sector. Unfortunately member states are currently using a number of international, regional and local standards that are often not compatible, with extra costs being incurred in aligning those standards. To minimise obstacles to cross-border trade, legal uncertainty and the administrative burden and to standardise the process of data interchange, it is important that member states should adopt common requirements for electronic data interchange. Under Directive 2014/55/EU of the European Parliament and of the Council of 16 April 2014 on electronic invoicing in public procurement, the public sector must from 27 November 2018 become a user of the electronic invoice, an essential step towards standardising the process of electronic invoicing across the EU. This article explores guidelines of the directive.