Changing the email signature on your apple iphone 6 is just another way to personalize it a bit more. Instead of the generic sent from iphone that people see when they receive an email from you, you can have it say sent from Edward or whatever you choose. To change this feature first go into the settings and scroll down to mail. Then you should see a signature option. Simply click this option and change it to whatever you want your email signature to be on your apple iphone 6.