Thanks for joining in on this thread, countryclubdev.
I'd like to clarify some information. When you say QuickBooks 2019, do you mean that you have the desktop version of QuickBooks? If so, the program uses the last saved invoice template as the default for the next invoice.
You can go to Customers > Create Invoices and review the current template selected. Here's a sample screenshot for a visual reference:
If you want to customize the template, you can go to the Lists menu and select Templates. For more customization, please feel free to read this article: Use and customize form templates.
On the other hand, the steps provided by Rebecca - Product Champion is for QuickBooks Online. This is a web-based software where you use a web browser to log in to your account.
Here's a sample screenshot of the page where the settings is located: