Only the owner of the organization has the authority to delete it.
Warning: This action permanently and irreversibly deletes all users, roles, circles, and all content. This action is irreversible. It cannot be undone.
The steps to follow to delete your organization are:
Click on your profile icon at the bottom of the left-hand navigation menu
Click on Administration
On the General Settings page, scroll down to Delete this organization
Click on Delete organization, and, Enter your password
Click on Save