An invoice origin declaration is a statement by which the exporter certifies directly on the commercial invoice (or other commercial document) that goods originate in a specific country, enabling preferential duty rates on import. Unlike the EUR.1 certificate, which requires customs endorsement, the invoice declaration is drafted and signed by the exporter without customs validation. When to use it: 1) For shipments up to CHF/EUR 6,000 — any exporter can use it without prior authorisation; 2) For any value — only authorised exporters (with BAZG authorisation in Switzerland or competent customs authority in the EU) may use it without value limits; 3) Under the EU REX system (Registered Exporter System) — REX-registered exporters self-certify origin for exports to GSP beneficiary countries. The declaration text must follow the standard wording specified in the applicable free trade agreement. Key points: the declaration must be hand-signed by the exporter (authorised exporters may omit this in certain cases); it must state place, date and exporter's name; it is valid for 4 months, like the EUR.1; the exporter must retain supporting documentation (material lists, supplier certificates) for at least 3 years; a false or inaccurate declaration carries administrative and criminal penalties plus recovery of unpaid duties. Digitalisation: with progressive customs digitalisation, the invoice declaration is gaining importance over the paper EUR.1. The EU's 2026 customs reform envisages a transition to electronic origin self-certification systems. The invoice declaration is the most practical and fastest method for certifying preferential origin, especially for SMEs with frequent lower-value shipments.