When you become a customer of the iTunes Store, your credit card information is saved to make future purchases an easy process. Your information is protected by your password and by Apple's servers. However, you may decide that you no longer wish to use the card you have on file, or that you prefer a different online music store. Edit your iTunes account information to remove your credit card information.
Launch iTunes and click "iTunes Store" in the left navigation pane.
Click the "down arrow" next to your name at the top right side of the page and click "Account."
Enter your username and password and click "View Account" to log into your account information.
Next to your Payment Type, click "Edit."
Select the "None" button and click "Done."
Confirm that your card has been removed by returning to the Apple account information screen. Under Payment Type, it should say that there is no credit card on file.