How to Deleting a Tenancy and Oracle Cloud Account

Try to clean up your Oracle Cloud Account and Tenancy?

You can delete your Account / Tenancy by following the steps mentioned in the link below:

1. While signed in as an OCI administrator, open the Tenancy Details page.
Otherwise, if not signed in as an administrator, the Request tenancy deletion button isn't available.
Click Request tenancy deletion.

2. The Request tenancy deletion confirmation is displayed
Confirm deletion in Enter the tenancy name to confirm deletion by entering the name of the tenancy to delete.
Click Request tenancy deletion.

3. A message is displayed to indicate that you successfully created a work request to delete the tenancy.
Under Work requests, a Tenancy deletion requested operation appears, where you can view the status of the deletion request.
The work request operation displays the state, percent completion, date, and time accepted, and when the operation started and finished.
You can also click the Delete Tenancy work request to view the Delete tenancy work request details page.
You also receive an email notifying you that the tenancy deletion process has completed.

Reference:
Deleting a Tenancy and Cloud Account
Viewing the Tenancy Details Page