But I notice that you don’t actually need to amend sales invoice to tax invoice, as when you implement the tax, it will auto update your heading to Tax Invoice.
@MHH, your version is out of date. View templates are no longer supported. They have been replaced by custom themes:
There have also been changes since your version in the way item codes, item names, and descriptions are shown, because many people were using them incorrectly.
Some built-in tax codes automatically substitute Tax Invoice for Invoice. If yours doesn’t, see this Guide:
