One document among several
An invoice is rarely read on its own. It sits in a small bundle of paperwork attached to a consignment, and its authority comes partly from agreeing with everything else in that bundle. A certified translation of a Commercial Invoice in United Kingdom practice is therefore written with that company in mind, because a translated page that contradicts its neighbours is worse than no translation at all.
Translator credential and pre-requisites
The work is done by an ITI/CIOL-qualified certified translator, and the certification signed against it is what gives the page standing. Before sending, check the image runs from the header to the totals with no line cut off, since a missing line on an invoice reads as a discrepancy rather than as a cropping accident.
Where a translated invoice is wanted
Consignments crossing into a market with a different working language are the usual reason. So are business records that have to be intelligible to a partner, an auditor or an office abroad reviewing a transaction after the event. In each case the reader is checking the invoice against something else they hold, which is the thread running through all of these uses.
Acceptance notes
Certification of this type is accepted by UK authorities including UKVI and the GRO, and it takes the form of a signed statement travelling with the translated pages. An official translation of a Commercial Invoice in Plymouth is priced at £25 a page and returns in 2–3 business days, or within 24 hours where goods are already moving and the paperwork has to catch up.