Let me guide you on how you can make a default invoice template in QuickBooks Desktop, ScubaPro.
The previous answer above was applicable only to QuickBooks Online (QBO) products. For QuickBooks Desktop, you can make a default template by selecting the desired template when creating an invoice. I've included a screenshot for your visual guide.

After you've selected one, this will automatically select the same template once you enter and print an invoice. Another way is to set some of your templates to inactive, and the new template will have to remain active. Here's how:
- Go to the List menu, select Templates.
- Right-click the templates, with the exception of the new template, and then choose Make Template Inactive. This will remove from the active list of invoice templates.
Once you've set a list of templates to inactive, only one template is currently active and is set as default. This will also automatically print the information of your invoice and you don't need to select once. You can also import o export form templates in QuickBooks. Read this article for more information: Use and customize form templates.
In addition, you might encounter some issues when using a customized template. For your reference, check this out on how to fix this: Fix common issues when you use and customize templates.
Let me know if you have other concerns about the invoice template. The Community is always here to assist you.