how to edit the date format for invoice?

I can assist you with changing the date format in QuickBooks Online (QBO), @accounts591.

Changing the date format in the settings of your QBO account will affect the date formatting on invoices as well. 

Here's how: 

1. Go to the Gear icon at the top.
2. Choose Accounts and Settings.
3. In the left menu, choose Advanced.
4. Scroll down to the bottom, then select Other preferences.
5. Click the pencil icon beside the Date format.
6. On the Date format drop-down arrow, pick what date format you prefer.
7. Select Save, then Done.

Afterward, reload the page or log out and log back in to verify that the changes appear in the invoices.

Moreover, you can check out this article to learn how to personalise your sales forms: Customise invoices, estimates, and sales receipts in QBO. 

If you need further assistance with managing your invoices or have any QuickBooks-related concerns, please feel free to reach out to the Community. I'd be glad to assist. Have a great day.