Adding existing Contacts
Creating new Contacts
Accessing friends from social networks
Contacting a Contact
Even if your iPhone is your only device, Contacts is a sort of hub for your iPhone activities. Many of the apps on your iPhone retrieve data from Contacts to perform their functions: Phone accesses Contacts to call a stored phone number or FaceTime address, while Messages and Mail rely on Contacts to send messages to stored mobile phone numbers and e-mail addresses. Contacts use isn't limited to communication apps; for example, both Calendar and Reminders access Contacts for information about people or places with whom you have appointments. Third-party apps may use the information in Contacts, too.
If you already have an iPhone-compatible electronic address book, one of the first things ...