How to Add New Information to a Contact from E-mail Message (iPhone/iPad iOS 10)
If you receive an e-mail from someone not in your Contacts, you can quickly add them with the tap of a button that automatically appears at the top of the message. This information is derived from their e-mail signature. If you already have a Contact, but when a new phone number or e-mail is detected, you can add this new information to an existing contact.