If you have an email address you no longer need on your iOS device – Delete it.
On your iPad, iPhone or iPod touch navigate to Settings >> Mail, Contacts, Calendars. Under Accounts, tap on the email address you want to delete.
The mail settings screen comes up. Tap Delete Account.
Verify you want to delete the account. That’s all there is to it.
To add an account, check out our article on how to add an email account to your iDevice.