Simply learn yourself.
For itunes

How to Review or Verify Payment information in iTunes

It is important to verify the payment information for the iTunes before you use it for the payment information purpose. When iTunes says verify payment then it is problem with the iTune store not with the bank account. Here are easy steps to resolve it.

Step One

If you are getting this message from the iTunes then you can review the card information.

Step Two

Now try to purchase the song or app and then when you hit install or get, the same message will appear that says ‘hit review’.

Step Three

Now fill up the required information needed and then hit done available on the right bottom corner. If this thing works then you will never receive this message again.