We appreciate your sharing this matter with the community, excavate.
Upon checking further, it appears that your concern regarding including ABN on invoices has already been addressed by my colleague.
Please refer to this link for more information: https://quickbooks.intuit.com/learn-support/en-au/manage-customers-and-income/re-how-do-i-put-the-au...
Feel free to post again in this vibrant forum for any other QuickBooks-related concerns. We're here to lend a hand.