Software: Intuit QuickBooks accounting software
Although, the foreign currency invoice does show a base currency equivalent amount and an exchange rate used in the invoice, these fields are not available for print.
Since the User defined fields in the template are limited, you may consider adding the base currency equivalent amount at the description area of the sales invoice (after the last item sold).
Assume your base currency is the Singapore dollar (SGD), you may add the below information into a foreign currency invoice.
Total amount payable excluding GST in SGD:
Total GST (7%) payable in SGD:
Total amount payable including GST in SGD: