Apple ID is a personal account that can be used to avail Apple service like iTune store, iCloud, FaceTime, etc. Billing information verification is also important as it verify your credentials as well as billing address. Here are some troubleshooting tips for you.
First, open the latest version of the iTunes in your device. Now choose STORE > SIGN IN.
In the SIGN IN option, enter your Apple ID as well as password and then tap on Sign In.
Now you will have a page, hit on your name over available on the top right side.
Now ‘select account info’ as well as ‘enter password’, pick edit in payment type, enter your billing information.
Now Click Continue. You can also remove or edit using your credit card information.