1. Unlock the phone interface and find the "Settings" option. ?

2. Find "iTunesStore and AppStore" under the settings page. ?

3. Click on the appleid account under the iTunesStore and AppStore pages, and select "View AppleID".

4. Enter the AppleID password and log in. ?

5. Log in and click "Payment Information" under the account setting page. ?

6. Under the "Payment Method" option, we can change the original payment method to "None" and finish.