Welcome to the Community, @rtwogood. I understand that you want to have the required fields when in the invoice.
At the moment, this option isn't available in QuickBooks. I can see that this kind of feature is very relevant to you and your business. I'm taking note of this idea in the hope it will be available in future updates.
In the meantime, you can also use the Memo or the Description field to add notes in the transaction.
You'll want to explore more options to customise your invoices, estimates, and sales receipts to add custom fields to it.
Get back to us here in the Community if you have other questions, @rtwogood. I'm always around here to help.