For businesses not registered for GST/VAT, there is an option of use zero GST/VAT rate for all transactions regardless what are stated on the invoice.
"Convert Invoice to Tax Free" is an EzzyBills Setting, under Advanced Options. If it is ticked, we will export all bills and expenses to your accounting software as Tax Free. The invoice total will include the tax (but with tax code as tax free).
This option is available for both Xero and QuickBooks Online users.