how to change Gmail account User Name

You can change the name that's linked to your email address, but not the email address itself.

Old:

Hiking Fan hikingfan@gmail.com to me

New:

Bob hikingfan@gmail.com to me

1. Open Gmail on a computer.
2. At the top right, click the gear .
3. Select Settings.
4. Click the Accounts tab.
5. In the “Send mail as:” section, locate the email address you'd like to edit.
6. Click edit info next to the address.
7. In the “Name:” section, specify what you’d like your name to be and click Save changes.

for more Information please visit this link.. https://support.google.com/mail/answer/8158?hl=en&ref_topic=3394465