Update payment method.

This document explains how to 'Change, add, [review,] or remove Apple ID payment methods' on an Apple mobile device, a Mac, or a PC; click here --> https://support.apple.com/HT201266

- If you are updating an old card and have ongoing subscriptions you may need to first add the new card and make it the primary payment method before deleting the old card.

'If you can't remove your last payment method or use no payment method with your Apple ID' click here --> https://support.apple.com/HT203905

If you still have problems Click here --> https://support.apple.com/choose-country-region/media-services Select your country, then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

or:

Contact Apple for support and service --> "See a list of Apple phone numbers around the world." - https://support.apple.com/HT201232

Additional resources:

'Payment methods that you can use with your Apple ID' --> https://support.apple.com/HT202631

'If your payment method is declined in the App Store or iTunes Store' click here --> https://support.apple.com/HT203005

I want to update my credit card information

Read the Apple Recommended post here for the answer.

I want to update the expiry date on my credit card - to pay for my iCloud 50GB Storage Plan.

How do I do that?

Read the information in the thread. The answer is provided.

I need to change bank account for this monthly charge. How do I do this?

Read the response above. The answer lies there.