Name: Your Name (What ever you want)
Email: Your username
Password: Your gmail.com account password
Description: Gmail
Click Next Button
Hostname: imap.gmail.com
Username: Your username
Password: Your gmail.com account password
Hostname: smtp.gmail.com
Username: Your username
Password: Your gmail.com account password
Click Save Button
Use SSL: Yes
Authentication: Password
Server Port: 993
Use SSL: Yes
Authentication: Password
Server Port: 465
You can login gmail.com and Signup for gmail.com new account on your iPhone from here.