Great job with the research you've already done with adding different sales taxes on an invoice. I'm happy to pick it up from here and show you how to add multiple sales tax codes to a single invoice. It's very easy once you know how it's done.
To have different tax codes on an invoice, it's as simple as assigning tax codes to lines. For instance, it might look something like this.
Item 1 — HST ON
Item 2 — GST/QST QC
Item 3 — GST
And so on. Once you've assigned tax codes to your line items and have filled out the rest of the details, simply hit Save or one of the other Save options as needed.
The beauty of QuickBooks is that it'll give you a break down of each tax total in the Subtotal section of the transaction. That way you know what was calculated based on what you entered.
If you're not sure which tax codes you should be applying, feel free to touch base with an accountant. If you have an accountant already, you can invite them to your account using the field in the My Accountant tab. You can use that same tab to find an accountant by using the Find a Pro to Help option and entering your postal code or city to begin searching.