How to Permanently Delete Your Gmail Account
Your decision to delete your Gmail account is final. You cannot retrieve your account once it has been deleted, including any associated data.
Follow these instructions to delete your Gmail account.
Log in to your account through the Google Account website.
Select "Data & privacy" from the menu.
Click "Delete a service" after navigating to the "Data from apps and services you use" section.
Select "Gmail" from the list of "Choose a service to delete"
Select "Delete service."
After providing your password, select "Next."
Click "Delete Gmail" after reading the information about what will be destroyed.
Your Gmail account has been terminated.