Visit this page using Safari on your iPhone / iPad.
Enter your email address and name, and touch "Download My Profile". An email account Profile will be sent to your iPhone / iPad.
When prompted, install the Profile (touch "Install" at top right).
When prompted, enter your email password to complete the setup.
You may then close this page in Safari. Open your Mail app and you'll see your new email account ready for use.
To remove this email account from your device, delete the Profile.
On your device navigate to: Settings > General and scroll down to Profiles. Select the profile for this email account and touch "Delete Profile".