Hi, @lgrisola22.

You can customize the email format through the Sales tab on the Accounts and Settings or in the Custom form style. Please know that this only applies to the messaging, excluding the amount due.

To personalize how the amount due displays on your invoices, I recommend sharing feedback with our product development team so they can consider incorporating this feature in future updates.

Here's how to do that:

1. Head to the Gear icon.
2. Select Custom form styles.
3. Choose a template and hit Edit.
4. Go to Emails and Give Feedback.
   
5. Input your thoughts, then Submit. 
   

You can explore this article for more configuration options in tailoring your sales templates: Customize invoices, estimates, and sales receipts in QuickBooks Online.

We're a click away if you need anything else.