Thank you for keeping us updated about the email template, Creegz.

In QuickBooks Desktop, you're unable to edit the email message to an existing invoice template. 

You'll have to add a new template and make modifications so you can use it when sending invoices to your customers.

Here's how:

1. In your QuickBooks Desktop, go to the Edit menu, then select Preferences.
2. Click Send Forms and go to the Company Preferences tab.
3. Select Add Template.
4. In the Add Email Template window, enter the correct information and click Save.

Just in case you'll want to personalize your invoice, you can check out this article for the detailed steps and information: Use and customize form templates.

Please keep me posted for all of your QuickBooks needs, I'm always glad to help send your emails to customers. Take care and stay safe!