b2b3 business to business3 woocommerce3 checkout1 custom price1 discount1 dokan supported1 e-commerce1 ecommerce1 fatturazione elettronica1 invoice1 messaging1 multivendor1 number1 order number1 payment gateway1 pec1 purchase order1 quotation1 rfq1 sdi1 supplier marketplace1 tax1 validate1 vat1 vat field1 vat number1 vendor1 wholesale1 woo commerce1