Can I change the default email for invoices?

You can change the default email address from your invoices through the editing work invoice. I'd be glad to walk you through the steps to achieve this.

This can be done both in old or new invoices. I'll attach screenshots with the steps for better reference:

1. Go to the Invoices menu and select any invoices.
2. Click the Edit work info hyperlink. 
3. Change the address and hit Save. 
4. Click the Preview tab on the bottom left and check the address.
   
   

I'm adding this article you can use in  the future: Create and customize invoices in QuickBooks Self-Employed.

You can always leave a comment below if you have follow-up questions about managing your invoices in QBSE. I'm continuously here to assist you. Take care!