How to delete an email address?
1. Sign into My Account.
2. On the left side of the screen, select Data & privacy.
3. Scroll down to the Data from apps and services you use section, and under Download or delete your data, click ”Delete a Google service.”
4. Enter your Google password.
5. On the Delete a Google service page, locate the Gmail service and click the trash icon next to it.
6. Enter an alternative e-mail address, where Google can send the confirmation link to delete your Gmail account. Then click the Send verification email link.
Hope this helps!