Since November 27, 2020, electronic invoicing has been mandatory at federal level for all suppliers and contractors who provide services for federal authorities. This means that invoices must be submitted in XRechnung format or an equivalent, EU-compliant format; paper or PDF invoices are no longer accepted. This is based on the Federal E-Invoicing Ordinance (ERechV), which transposes EU Directive 2014/55/EU into German law. The aim of this regulation is standardized, digital and automated invoice processing, which increases efficiency, transparency and traceability in public administration. As a rule, invoices are transmitted via the federal government's central invoice receipt platform (ZRE) or the OZG-RE.