Thanks for letting us know about the add field behavior, @DwhoaTreas.

I'll share some information about adding the customer's name to the invoice. While this option is unavailable, you'll want to follow the steps provided by my colleague @SashaMC as a workaround.

With the steps above, you're able to see the "Customer Name" field in the header portion and then enter your customer name on the invoice. This is how it looks like.

About the new customer (address field), I'll be sending a product feedback to our Development Team on your behalf.

I'm also attaching this link here in case you need help with other tasks in QBDT. Just browse for topics that suit your concern.

Let me know if you still have questions or concerns with customer or invoices. I'll be around for you. Take care and have a lovely day ahead.