Hi there, FlexFl. I can see the importance of modifying the email template for your invoices in QuickBooks Desktop (QBDT). Let me share some information about this feature.

QuickBooks is constantly getting a makeover for product updates and improvements. The look and feel of sending invoices from our system may be different, but the same ease of use and effectiveness will remain. The good news is that you can always modify your forms and templates through the Preferences window.

Here's how:

1. Open your file.
2. Go to the Edit menu, then Preferences.
3. Tap on Send Forms.
4. Click on Company Preferences.
5. Choose the template you're using, then Edit.
6. Start to alter the details from there.

I'm also adding this article for more reference: Create custom email templates in QuickBooks Desktop. 

To learn more about invoice layouts, you can open these articles:

• Use and customize form templates
• Email sales forms, invoices, and statements in QuickBooks Desktop

If you have other concerns while emailing your transactions, let me know by leaving a comment below. I'm more than happy to help you again. Have a good one!