for iOS 9.1 software

Use a gift card or code. Tap Featured, scroll to the bottom, then tap
Redeem.
Send a gift. View the item you want to give, tap , then tap Gift. Or tap
Featured, scroll to the bottom, then tap Send Gift to send an iTunes gift
certificate to someone.
Restrict in-app purchases. Many apps provide extra content or
enhancements for a fee. To limit purchases that can be made from within
an app, go to Settings > General > Restrictions (make sure Restrictions
is enabled), then set options (for example, restrict by age rating or
require a password immediately or every 15 minutes). You can turn off
In-App Purchases to prevent all purchases. See .
Use iTunes Pass. You can add an iTunes Pass to Wallet, which makes it
easy to add money to your Apple ID so you can make purchases from the
iTunes Store, App Store, and iBooks Store without using a credit or debit
card. To add your iTunes Pass in App Store, tap Featured, scroll to the
bottom, tap Redeem, then tap Get Started under iTunes Pass. You can
add money to your iTunes Pass at Apple Retail Stores in most countries.
App Store settings
To set options for the App Store, go to Settings > iTunes & App Store.
View or edit your account. Tap your Apple ID, then tap View Apple ID.
To change your password, tap the Apple ID field, then tap Password.
Restrictions