Can I create an invoice form in which the subject of the email has automatically the customer's full name instead of the invoice number? thank you.

Hello @userkorovesis,

Welcome to the Community. I can provide some clarification about the invoice form in QuickBooks.

Currently, you can only show the customer's complete name automatically by adding the information to the invoice number field. Since a specific setting for the feature is unavailable, the only option is to update the details from the Subject field manually.

In case you need the steps, here's how:

1. Create an invoice.
2. Enter the necessary information.
3. Click Save and send.
4. Edit the information from the Subject field. 
5. Hit Send and close.

Please know that I appreciate your input on this feature. We'll continue to improve QuickBooks Online, and this preference might be available in the future.

As we assess this, I invite you to visit our QuickBooks Blog to stay updated with all the changes with the product.

For more information, as well as how to customize the invoice form in QuickBooks, I recommend the following article: Email and customise sales form.

Keep us posted if you need anything else regarding the setup. Have a great day!