Sign in to your Google Account
Go to myaccount.google.com
Select Data & privacy
Scroll to Data from apps and services you use
Click Delete a Google service
Sign in again if prompted
Find Gmail and click the trash icon
Enter an alternate email address for signing in to other Google services
Check the confirmation email sent to that address
Open the email and follow the deletion link
Confirm the deletion of Gmail
Review any remaining Google services linked to your account
Save any important emails before deleting Gmail
Update email addresses on other accounts that use your Gmail address