Good to see you here, @smart1.
To run a final VAT return, you’ll want to make sure to mark your VAT as filed in QuickBooks to close the period.
Here’s how:
- From the left navigation pane select Taxes.
- Click VAT.
- Select Prepare return to view your open return.
- Once you're done, go back to QuickBooks Online and select Mark as Filed.
For further information about VAT return preparation, please see this article as your reference: Submit a VAT return in QuickBooks Online.
We'd recommend confirming with HMRC if you have any queries on this ,if you are MTD registered and need to file that way as long as HMRC have set obligations(the dates for the filing) for the final return you will be able to file it.
Keep me posted if you have other concerns. I’ll be around.