Hello, @ECSG2017.

You can choose the invoice template before you create it.

Here's how:

1. Click the New Icon (+).
2. Choose Invoice.
3. From the bottom portion of the Create Invoice window, click the Customize link.
4. Select the invoice template you want to use. 
5. Enter the invoice details.
6. Click the Save and Close button. 

Keep us posted here if you have other questions about using your customized sales forms in QuickBooks. I'm always here to help.