What it means
The UK vehicle registration certificate, commonly called the log book. It records vehicle details and the registered keeper.
Check the details when it arrives after an import registration, and follow DVLA’s correction process if something is wrong. It is distinct from the foreign registration document you used to support the application. A V5C is a registration record, not proof that the named keeper owns the vehicle.
Keep the document reference number private and avoid publishing images of the certificate. Retain purchase evidence separately. For an import, the V5C also provides accepted evidence of entitlement when arranging plates through a registered supplier.