How can I change my Billing address

I just relocated to another continent

If you change Country or Region, you must comply with all regulations described here ->  Change your Apple ID country or region -> Change your Apple ID country or region - Apple Support (KW)

⤵️

What to do before you change your country or region

• Spend any balance remaining on your Apple ID. If you're not sure whether you have a balance, check your Apple Account balance.
• Cancel your subscriptions and wait until the end of the subscription period. 
• Wait for any memberships, pre-orders, movie rentals, or Season Passes to complete, and wait for any pending store credit refunds to process. You can cancel a pre-order.
• Make sure that you have a payment method for your new country or region. See what payment methods you can use.
• Redownload your apps, music, movies, TV shows, and books on any devices that you might use to play or read them in the future. Some types of content might not be available in your new country or region. Learn what types of content and services are available in your new country or region.

1.

You need to ZERO your Apple ID balance, it is depending on the amount:

1.

If your balance is less than the cost of a single item, contact Apple Support directly, they will help you clear your balance: Get Support

2.

See -> Check your Apple ID balance

Check your Apple ID balance – Apple Support (UK)

scroll to ⤵️

If you have Apple ID balance you can't use.

You can't redeem or return Apple Gift Cards, App Store & iTunes Gift Cards or unused Apple ID balance for cash, except as required by law. If your jurisdiction allows the refund of redeemed gift balances, you can contact Apple Support to request a refund. 

When you contact Apple, include the following information:

•           Your Apple ID.

•           The refund amount.

•           Your current delivery address. 

2.

You need to Cancel your subscriptions and wait until the end of the subscription period. 

3.

Make sure that you have a payment method for your new country or region. See what payment methods you can use.

You need to have a debit / credit card issued by a bank in your new country.

You need to have a billing address in your new country.

Did you follow the steps mentioned in this article?

...

...

copied from: Change your Apple ID country or region - Apple Support

You can also do this manually:

...

...

copied from: If you need to change or update your Apple ID payment method - Apple Support

Also remember, that the billing address has to point to the registered payment method, for example the banking location for your credit card.