Before you can buy anything from the App Store, you need an Apple ID. When you create an Apple ID, you also need to provide a payment method for your purchases.
The available payment methods vary by country. You can typically use these methods:
- Credit cards
- Content codes
- Store credit, including iTunes Store Gift Cards, Gift Certificates, and Allowances
- ClickandBuy
- PayEase
- PayPal
- UnionPay (requires SMS PIN for setup)
For more details click here to read Payment methods for iTunes and App Store.