how to delete gmail account

Download all your data before deleting your gmail account

open device setting in your phone click on the apps and select google

tap on manage your google account option

tap Data & privacy option given in the top

Scroll to "Data from apps and services you use.

you will see a option download and delete tap Delete a Google service. You might need to sign in.

after signing in tap Delete and before your account is deleted you have to sign in with existing email adrees 

code will be sent to your existing email adress after varifying the code your gmail account will be deleted 

you can not delete your gmail acount without verifying the code