When you send an email from your iPad – the default signature is “sent from my iPad”. That’s boring and uninformative. Here’s how to customize your email signature on your iPhone, iPad or iPod touch.
Open Setting and select Mail, Contacts, Calendars. Scroll down the screen and tap Signature.
Now in the Signature box, enter in your own custom signature. Include the information you want the recipients to have.
The new email formatting option in iOS 5 works here too.
That’s it! Now every email you send from you iOS device will have the the new signature you made.