If you complete onboarding (filled your profile and got access to the app):
If you just created a new account, click on the red "Abort" button. It will imeediately delete your account and log you out. 
If you used Telegram auth method, you can just write @ami_app_bot from the account you registered with the request to delete your account.
If you have troubles deleting your account, you can write us via email ([email protected]) or via Instagram and our support team will process your request manually.