Steps
Navigate to
Organization Settings > OverviewScroll to the bottom of the page where you'll find the delete option
Additional Notes
Your organization must be on the Free plan
You'll need organization admin permissions to complete the steps
Deletions may take up to 24 hours to fully process
For VCS (GitHub and Bitbucket) organizations: projects and data will be removed, but the organization shell will remain visible
For standalone (non-VCS) organizations: everything will be removed