1. Go to ‘Settings’
2. Tap on your Apple ID
3. Select ‘Payment & Shipping’
4. Tap on ‘Add Payment Method’
5. Select ‘Mobile Phone’
6. Tap ‘Done’
7. Dial *101*70# from your e& number and select a monthly cap limit

Your account will now charge all your purchases in the future to your mobile phone’s bill.

You can set up your account here.