paymentcashinvoice.php

См. документацию.

<?php
 
namespace Bitrix\Sale\Exchange\Entity;
 
 
use Bitrix\Sale\Exchange\EntityType;
 
class PaymentCashInvoice extends PaymentInvoiceBase
{
    public function getOwnerTypeId()
    {
        return EntityType::INVOICE_PAYMENT_CASH;
    }
}