U can't. There is no way of doing it. Iphones don't allow you to do it.
Answer
The only way you can put a signature on an iPhone (any handset), is via the email settings, rather than the default sent from my iPhone you can put anything you like in, that's as good as it gets for now. Go to settings, then email to make the change.
You can add a signature to your emails, via the iPhone 4. Go in to the email settings and you have the option to change from the "sent from my iPhone" to anything you want. This will hen be automatically added to all outgoing emails as your signature.
I think you can only have a signature on the email.
They don't have sigs.
You can't add a signature to the iPhone. Hopefully an iOS update will fix this. There is an app available in the AppStore called TextFree which allows you to have signatures.
:{ colan and whatever this is called{
You go under settings and mail and hit signature.
you cant so stop trying
You cannot create a auto insert signature line for texts via the iPhone. The only facility that has this is email. You can add a signature script in place of "Sent from my iPhone". Same as for the iPad.
Yes, go to Settings, Mail, Contacts, Calendar then in the mail section there is a Signature option.
160 is what I heard and i have one sooo i think im right
Go talk to people, select chat, ask for signature
No . But there are ways to get it .Look it up on YouTube ! Hope This Helps !!