Hi there, buldog1.

Thanks for joining this thread. I'm here to help and walk you through on how to customize invoice template in QuickBooks Desktop for Mac. 

To do this, please follow the steps below:

1. From the Customers menu, select Create Invoices.
2. At the top of the invoice, select the Invoice template selection button.
3. Choose Edit Template.
4. This opens the Layout Designer view.

You may check this article on how to use and customize form templates.

If you need further assistance with the steps, I recommend calling our QuickBooks Desktop Mac Support. They have the tools to pull up your account and do a remote session. 

Here's how you can contact our phone support: 

1. Click this link: https://help.quickbooks.intuit.com/en_US/contact.
2. Select the version of QuickBooks, click Contact Us.
3. Type-in Customer Support on the search bar. 
4. And click Get the Phone number below. 

This will get you on the right track. Please know that you're always welcome to post if you have any other questions about customizing invoice. Have a good day.