As of the moment, there isn't an integrated way to delete an account in QuickBooks Self-Employed. But don't worry, you can cancel your subscription and the system will automatically delete your data after a year of inactivity.
That said, let me walk you through the steps on how you can cancel your subscription:
Don't hesitate to post again here if you have other questions or concerns with QuickBooks tasks and navigations. I'm always around happy to help. Take care and stay safe!