Q: How can I change my Apple ID from MasterCard to itunes card

Hello there, EMRE.KURT999.

The following Knowledge Base article offers up some great information on how to change your payment information and links to what forms of payments are accepted:

iTunes Store: Changing your payment information

http://support.apple.com/kb/ht1918

If it's how to redeem your iTunes gift card that you are asking about, then this article has that information for you:

Redeeming iTunes Gift Cards and content codes

http://support.apple.com/kb/ht1574

Thanks for reaching out to Apple Support Communities.

Cheers,

Pedro.