You can customise your invoice template, bigdogautopd-gma.
Note that this will only affect invoices created moving forward. Follow the steps below:
That's it! Your Australian Business Number will now appear on your invoices. You can also customise other sales forms in QuickBooks: Customise invoices, quotes, and sales receipts in QuickBooks Online.
Let me know if you need anything else, I'll be more than willing to help.