Unable to add card to payment method in Apple Account

Make sure that your payment method and your app stores country settings are the same

After that try this

1. On your iPhone or iPad, open the Settings app.
2. Tap your name.
3. Tap Payment & Shipping.
4. Add a different payment method and remove the old one. 
5. Try to complete your purchase.

If you still can't make a purchase

• You might have an unpaid order. Learn how to pay an unpaid order.
• Contact your financial institution. 
  • You might need to ask your financial institution to allow international purchases on your debit or credit card.
  • If you want to know why a debit card, credit card, or other payment method was declined, speak with your financial institution. Apple doesn't have information about why the payment method was declined.
• In some countries and regions, your payment method might be declined because of changes to local law. Learn about billing and purchases in Europe.

Read this document about how to view your current payment types and add Apple ID payment methods on an Apple mobile device, a Mac, or a PC --> Add a payment method to your Apple Account - Apple Support

If an item appears in red then it is no longer working and you either need to replace it or get it working again. Apple may require the presence of a valid payment method such as a card, even if an app is free. You won't be charged but the card has to be there and in working order.

Check this resource about what to do if your payment method is declined in the App Store or iTunes Store. Click here --> If your payment method is declined in the App Store or iTunes Store - Apple Support

- Apple is checking with your financial institution if the payment method is valid and receiving a negative, or no, response. Make sure the name and address are entered exactly as it appears on your financial institution bills and that the 3 digit CVV is correct. Check with your financial institution about the status of your card.

- Make sure your payment method is up to date or to try a different one ( If you need to change or update your Apple Account payment method - Apple Support ).

- Make sure this is one of the payment methods that you can use with your account, as listed in this support article: Payment methods that you can use with your Apple Account - Apple Support .

・Unfortunately the payment methods list is somewhat general and does not include individual brands of cards (I guess there are too many and are constantly changing). This thread is an example of where a person was not using an acceptable kind —> Why are my cards not supported on the MFI… - Apple Community

・Also read any footnotes in the document.

・If you are trying to use a payment method from another country you may encounter problems. Apple nowhere states outright your payment method must come from the same country as that to which your ID is set, but some contributors to the forum (none of us work for Apple) say—without any substantiation on Apple's part—this is the case. In fact what Apple says about international payment methods is found in If your payment method is declined in the App Store or iTunes Store - Apple Support where it says: "You might need to ask your financial institution to allow international purchases on your debit or credit card". It could be there is some other unstated requirement that raises problems such as the billing address for the card must be in the same country as your account country even if the issuer is a foreign bank. Apple does not say but usually it is easiest to just use a card from the same country as your Apple Account setting.

・Finally, note that the document only says which methods _are_ acceptable. Apparently certain types (usually a credit or debit card) _must_ also be present under certain situations such as when a subscription is involved.

If you still have problems, contact official Apple Support. Click here --> Choose your country or region - Official Apple Support 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:

See a list of Apple phone numbers around the world, in this article --> Contact Apple for support and service - Apple Support

If you're in India, click on this link to read an April 2022 notice 'About billing for Apple subscriptions and media products in India' --> About billing for Apple subscriptions and media products in India - Apple Support

Additional verification that may be required when making purchases in Europe --> About billing and purchases in Europe - Apple Support