Good evening, @julest.
At this time, there's not a way to edit a Packing Slip in QuickBooks Online. I'm going to submit feedback to our Development Team about bringing in this feature.
You can visit our Blog to learn what new updates are being released to QuickBooks.
Here's an article on how to create and print a packing slip.
Don't hesitate to get back to me if you have any additional questions. Have a nice day.
