As of this week, the feature is now supported by EE in the United Kingdom, Orange in France and Spain, and Telekom or T-Mobile, which are owned by the same company, in Austria, Czech Republic, Germany, and Slovakia.
The payment method enables customers to pay for iTunes Store content, App Store apps, iBooks, and Apple Music subscriptions without needing a debit or credit card, or even a bank account. Instead, purchases are added to a customer's mobile phone bill and paid off at the end of the month.
The payment method was already offered by select carriers in Austria, Belgium, Denmark, France, Japan, Hong Kong, Italy, Norway, Russia, Singapore, Spain, Sweden, Switzerland, Taiwan, Turkey, Saudi Arabia, and the United Arab Emirates.
Apple's support document explains how to set up mobile phone billing in the iTunes Store on both iPhone and iPad or Mac and PC.