CC expiration date

If the payment method is added as part of your iTunes account, you need to see this, Change, add, or remove Apple ID payment methods - Apple Support If it is a credit card that you just saved in Safari, then go to Settings>Safari>AutoFill>Saved Credit Cards. Otherwise, it may just be one you have saved in a particular merchant's website account.

How do I change expiration date on my cc

Read the link I provided in my post. That provides you the information, all you need to do is read it.