Follow these steps to remove an email account from your iPhone:
1. Locate and press the Settings icon.
2. Select Mail, Contacts, Calendars.
3. Choose the Email Account you want to remove from your iPhone.
4. Press the red Delete Account button.
5.Confirm the deletion by pressing the red button.
Note: Deleting an email account from your iPhone will also remove all messages associated with that account on your device.
That’s it! The email account has been deleted from your iPhone and is no longer listed.