I can share some information about editing your invoices, @TP34.

Can you tell me more about the information that you're trying to update with your invoices? That will help me provide an accurate solution to the concern you're having. 

As mentioned by Kevin_C above, you can change the product/service item of the invoice without deleting other information. Other information aside from the setup of your item like the description, quantity, or rate, will also update when you change it. Follow the steps below on how to update the invoice.

Here's how:

1. Go to the Sales menu and select Invoices.
2. Select to open the invoice.
3. Click the Edit invoice button.
4. Update the necessary information.
5. Click on Save once you're done. 

Here's more information about managing your invoices in QuickBooks: Create invoices in QuickBooks Online.

Once you received their payment, here's how to add them: Record invoice payments in QuickBooks Online. 

Let me know if you need more help with your invoices. I'm always here to assist. Have a wonderful day!