Was there a change to the UI (User Interface) of editing invoices and if so, how do we change it back to the previous style if possible?

I acknowledge, that using the old user interface for invoices in QuickBooks Online (QBO) is essential to your business, @agarcia-trade-fl.

Yes, there's a change to the invoice layout in QuickBooks Online. Please note that you can no longer switch to the old experience. However, I can guide you on how to edit your invoices in the new format.

First, you can go to the + New icon. 

1. Choose Invoice under Customers.
2. Click the Clock icon in the upper left corner.
3. Select the invoice, and then make changes under the Edit tab.
4. Click Save and Close to save the changes.

The second option is to go to the Sales menu. Here's how:

1. Go to the Invoices tab. Select the appropriate filter.
2. Select the invoices you want to edit.
3. Click on the Edit button. then make changes under the Edit tab.
4. Click Save and Close to save the changes.

For more details about it, check out this article: See what’s new with estimates and invoices in QuickBooks Online.

In addition, learn how to receive and record invoice payments in QuickBooks Online.

If you still have other questions regarding the invoice layout, feel welcome to add a reply below. I'll be glad to answer them for you.