If the previous owner is not present
Make sure the device is powered on and connected to a Wi-Fi or cellular network. Then contact the previous owner and ask them to follow these steps:
- Sign in to their iCloud account at www.icloud.com/find.
- Select the device from their Find My iPhone device list by clicking All Devices at the top of the screen.
- Erase the device by clicking the Erase button. This will erase all content and settings from the device. When prompted, do not enter a phone number or message. Click Next until the device is erased.
- When the erase is complete, click "Remove from Account" to remove the device from the account.
- After the device has been erased and removed from the account, you can proceed with the device setup process.