Trying to add abn to invoice but do not see option to do this?

Hello there, @jess_rouwhorst, 

The invoice doesn't have the field to add your ABN to the transaction. You'll first have to enter it in the Company menu. Let me guide you how. 

1. Go to the Settings (Gear) icon at the upper right.
2. Select Account and Settings under Your Company. 
3. Choose Company from the left menu,
4. Click the Pencil (Edit) icon of the Company name section. 
5. In the ABN section, make sure the enter the correct number. 
6. Select Save. 
7. Choose Done. 

The screenshot below shows you the third to fifth steps. 

Once done, let's check the ABN box in the Content tab of your invoice template. This will automatically appear on your sales form. Here's how: 

1. Go to the Settings (Gear) icon at the upper right.
2. Select Custom Form Styles under Your Company. 
3. Find your template from the list. 
4. Click Edit from the Action column. 
5. Go to the Content tab. 
6. Select the upper top of the invoice.
7. Check the ABN box. 
8. Click Done. 

See the screenshot below to show you the last four steps. 

To learn more about this process, go through this article: Customise Your Invoices, Quotes, and Sales Receipts in QuickBooks Online. You'll also find steps on how to change the basic design, layout, and info on your sales forms.

You can always go back to the Company menu in Accounts and Settings. This lets you update your business and contact info, including your ABN. For more information, check out this article: Change Your Business Name, Contact Info, or ABN.  

I'm just a post away if you need anything else. Have a great day, @jess_rouwhorst.