An Apple ID is a digital credential that belongs to an Apple customer. Apple IDs are used for identification purposes, and allow users to quickly purchase music or apps from the iTunes store. If someone sells his phone or gives it away, the iPhone can be reset to its factory settings and the new owner can create another ID.
Perform a Full Reset Step 1
Turn on the iPhone and tap the “Settings” button. Select “General.” Scroll down the list of options, and press “Reset.”
Tap the option labelled “Erase All Content and Settings.” Enter the iPhone’s passcode when prompted.
Press “Erase iPhone” to confirm the reset. Wait for the device to remove all of the user information, which can take several minutes.
Set Apple Id Step 1
Press the “Settings” button and select “ITunes & App Stores.” If an existing Apple ID is listed, tap the name and press “Sign Out.”
Tap “Create New Apple ID.” Press “Store,” and select your home country. Press “Done” and “Next.”
Review the terms and conditions for the Apple ID. Tap “Agree,” and then press “Agree” again to confirm.
Enter an e-mail address and password for the Apple ID. Type three security questions, which are used in case you forget the password. Tap “Next.”
Type a second rescue e-mail address when prompted. This is not required, but is useful for resetting the password if you cannot log into your account. Press “Next.”
Enter your billing information. This is used when you make a purchase on the Apple iTunes store. Tap “Done,” and then “Next.”
Press “Done” when the “Verify Your Account” screen displays. Check the e-mail address you provided for a message from Apple. Click the “Verify Now” link withing the e-mail.
Type the new Apple ID and password when prompted, and select “Verify Address” to complete the Apple ID setup process.
Reseting the iPhone removes all data, including music and photos from the device.