How to Change the E-Mail Settings on Your iPhone
You can customize the e-mail you send and receive in lots of different ways. There are four e-mail settings that you can change; you start by tapping Settings on the Home screen.
To hear an alert when you successfully send a message: Tap the Sound icon on the Home screen, and then turn on the Sent Mail setting. If you want to change other settings, tap the Settings button in the upper-left corner of the screen. If you’re finished adjusting your settings, tap the Home button on the front of your iPhone.
To add a signature line, phrase, or block of text to every e-mail message you send: Tap Settings, tap Mail, Contacts, Calendars, and then tap Signature. (You may need to scroll down to see it). The default signature is Sent from my iPhone. You can add text before or after it, or delete it and type something else. Your signature is now affixed to the end of all your outgoing e-mail.
To have your iPhone send you a copy of every message you send: Tap Settings, tap Mail, Contacts, Calendars, and then turn on the Always Cc Myself setting.
To set the default e-mail account for sending e-mail from outside the Mail application: Tap the Settings icon on the Home screen, tap Mail, and then tap Default Account. Tap the account you want to use as the default. For example, when you want to e-mail a picture directly from the Photos application, this designated e-mail account is the one that will be used. Note that this setting applies only if you have more than one e-mail account on your iPhone.