I've got you covered, @upleveldata. Let me provide some insights into the payment instructions within the invoice section in QuickBooks Online (QBO).

We understand the frustration of not having this function as expected and the importance of resolving it as soon as possible.

We have an open investigation for the same issue you stated above. We have asked Engineers to look into this issue and hope to have an update soon. 

What we can do for now is to edit the Electronic Fund Transfer (EFT) instructions per invoice while waiting for a better solution.  

Furthermore, I suggest contacting our support team to add you to the list of affected users. This way, you can receive a notification when a fix is available. Refer to these support hours for contacting us at your convenience.

In addition, follow this article on how to edit invoice templates, personalize, add, or remove unnecessary fields: Customize invoices, estimates, and sales receipts in QuickBooks Online.

I'm always happy to provide more information to our valued customers. Please comment on them again in this thread. My present help is always here in times of need. Thanks for your patience, @upleveldata.