Thanks for reaching out to the Community, @timbakitproducts.
I ensure you can get to submit your Value Added Tax (VAT) return using Making Tax Digital (MTD) in QuickBooks Online (QBO).
If you can't submit a return under MTD, it may be due to the MTD feature not being set up yet in QBO. When you set up, you'll need to provide the correct MTD credentials provided by HMRC via email. See this article for more details about the process: Set up MTD for VAT in QuickBooks Online and connect to HMRC.
However, if you have other issues that stop you from submitting the return, you can check this article for its fixes: Fix MTD issues and errors in QuickBooks Online.
In case you'll need to make adjustments in the future and manage VAT exceptions in the future, you can refer to these articles for guidance:
Keep us updated if you have clarification about managing VAT returns in QuickBooks. I'll always be around to assist you anytime. Have a great business!