Apple iOS: Delete Your Unused Email Accounts
If you have an email account you no longer use still hanging out on your iPad, iPhone or iPod touch, just delete it. Here's how.
On your iOS device, navigate to Settings >> Mail, Contact, Calendar. Then tap on the email account you want to delete.
The account screen comes up. Tap Delete Account.
When the verification message pops up, tap Delete.
Now you don't have an extra email account cluttering up your device.