You need to elaborate a little more on your query. ios will not ask for your credit card information directly. It will request you to create an apple id. You should take a screen image or a picture with a camera and post here.
Were are you trying to download something in app store?
To avoid having to enter you payment information, download a free app. You will need to create an apple id. You will be able to create the id without specifying your credit card information.