Whether you have an iPhone or an iPad, it turns out that it’s the same basic method for changing the signature. The default signature on the iPhone reads “Sent from my iPhone” and the default signature on the iPad reads “Sent from my iPad”. You might not want everyone in the world to know that you own an iPhone or an iPad and would like to change the signature to something like your name.
To change the default email signature go to “Settings” and then tap on “Mail, Contacts, Calendars” which will reveal a wide range of settings and preferences you can modify. Scroll towards the bottom and you’ll find Signature.
Tap on the Signature and you can change the text to whatever you want. Whatever you type gets saved instantaneously. There isn’t a need to save the signature. Once you come out of the settings, your new signature takes effect.