How to detele/remove accounts from aws organaizations if orgformation.yaml file is deleted.

Could you simply recreate the config file by running org-formation init organization.yml ? If you have lost access to your AWS organization root account, you should follow the instructions for password recovery https://docs.aws.amazon.com/IAM/latest/UserGuide/reset-root-password.html and then recreate your config. When closing (deleting) AWS accounts, please be mindful of quotas ;-)

https://docs.aws.amazon.com/accounts/latest/reference/manage-acct-closing.html