The Apple iPhone 6 comes with a native application called Address Book, which allows you to store contact information that can be used when making phone calls or searching for navigation directions. You can manually enter contacts in the Address Book or transfer them to your iPhone 4 through iTunes. When syncing with iTunes, you can transfer contacts from the Address Book application on your Mac or the Outlook program on your PC.
Open the iTunes program on your Mac or Windows computer.
Connect your iPhone 6 to the computer using the iPhone USB cable provided with the phone.
Click on the name of your iPhone 6 from the “Devices” section on the left side of the iTunes window.
Click on the “Info” tab at the top of the iPhone configuration window.
Check the box next to “Sync contacts.”
Select the program from which you want to transfer contact data. Mac users should choose ”Address Book” and Windows users should choose ”Outlook.”
Click the “Apply” button in the lower left corner to save the settings and transfer contacts to the Address Book on your iPhone 4.