How to add PayPal as payment method to your Apple ID
1
Unlock your iPhone and head to "Settings."
2
Tap your name, which is located at the top of the Settings page.
3
Tap "iTunes & App Store."
4
On the next screen, tap "Apple ID" then select "View Apple ID" and log in to your Apple ID account.
5
Once logged in to your Apple ID, tap "Manage Payments."
6
Tap "Add Payment Method," then select "PayPal" on the next screen.
7
Log in to your PayPal account and confirm that you're adding PayPal to your Apple ID account.
8
Done! When you purchase apps within Apple apps, your iPhone will default to using your PayPal account.