We mainly export to Central Asia and Russia. The proforma invoice is to list the goods and prices you export, and affix the official seal or special seal for export (usually a rectangular seal). This is the proforma invoice. Importers can take this invoice for customs clearance accounts. Of course, this kind of invoice is usually written according to the requirements of the other party, which is not necessarily exactly the same as the goods and the real export price. This invoice is generally used for customs declaration, and it is valid to stamp the export seal on the list of goods and the price. This invoice is used for customs declaration. We are usually the same as the proforma invoice, the only difference is the text, which is exported to Russia. The proforma invoice we sent them was in Russian, but the customs declaration was in English. I haven't heard of the third kind of invoice. Is it a write-off form purchased from the Inland Revenue Department? Used to write off payment for goods and collect foreign exchange. Without this, you can't receive foreign exchange.