Once I modify the template, the actual proposal does not reflect the change.
Welcome to the QuickBooks Community, ctstreeter01. Creating a new template for your invoices is best in this case.This way you can change how your proposal is viewed by the customer. This article shows how to customize each part of the form, and it includes a great video tutorial. You can change the template for an existing proposal by clicking the Customize button, which is in the gray menu bar at the bottom of the page. If you have any other questions, you can reach back out for support here.