Thank you for dropping by here in the Community, @cnomail.
In QuickBooks Online, you can configure the invoice templates and make changes to the information you want to show when creating the transaction. I suggest making sure you enable the ABN box from the sales form.
Here's how:
- Click the Gear icon at the top, select Custom Form Styles.
- Choose the invoice template and hit Edit under the Action column.
- Go to the Content tab and click on the Header.
- Make sure the ABN box is checked with the correct number.
- In the Display section, check the custom field box which contains other ABN number if needed.
- Select Done.
For additional information about how to customise invoices, check out the following article. It also contains detailed steps of the step by step process:
Customise invoices, quotes and sales receipts in QuickBooks Online.
I want to make sure this is taken care of for you. If you have any other concerns, post a comment below. I’ll pop right back in to assist further. Have a good one.