You can delete your account by going to Settings>Company
There you will be able to click on the delete button.
Only do this if you are sure!

What happens when you delete your account?
Users get deleted if this was the only account they belonged to
Data is permanently deleted
Workspaces are permanently deleted
Please note that you cannot delete a payment with an active subscription
You can cancel your subscription in Settings>Subscription
If you simply want to delete a specific Workspace, you can see how to do so here.