Use Express Replacement Service for your iPhone
With Express Replacement Service, you get a kit that has your replacement iPhone and everything that you need to send back your previous iPhone.
About Express Replacement Service
With Express Replacement Service, Apple sends you a replacement iPhone first — so you don't have to wait for a repair.
After you get your replacement iPhone, send back your previous iPhone right away. Apple must receive your previous iPhone within ten days after your replacement was shipped.
Your replacement iPhone is covered by a 90-day service warranty or the remainder of your AppleCare plan (or other original product warranty), whichever is longer.
Before you return your previous iPhone
Back up your iPhone
Erase your iPhone to delete your personal data and remove it from your Apple ID account: In Settings, tap General > Transfer or Reset iPhone, then tap Erase All Content and Settings. You need to enter your Apple ID password to confirm.
Transfer your cellular service to your new iPhone:
Power down your previous iPhone.
Pack your previous iPhone
Your Express Replacement Service kit includes everything that you need to pack up and send your previous iPhone to Apple — including the small white or natural box and large shipping box that your replacement iPhone arrived in, which you use to pack up your previous iPhone and ship it to Apple.
Place your iPhone into the small white or natural box in which your replacement iPhone arrived. Don't include anything else — like a phone case, power adapter, USB cable, or other accessory. If you include extra items in the box, they won't be returned.
Put the small box into the same large shipping box that was delivered to you. If there's a battery sticker pasted on the outside of the box, make sure it's not covered by tape or a shipping label.
Ship your previous iPhone to Apple
Apple isn't responsible for any damage during shipping.