I’m trying to change the card number on my subscription on iCloud, but is not allowing me

Nice to meet you, *****!
Do you see any error messages when you are trying to change the card?

Are you changing your payment method through your Setting app?

Are you adding a new payment method?

Okay, I see.
You can try adding the payment method on your Mac if you have that option.

Please follow the instructions below:

1. Open the Settings app.
2. Tap your name.
3. Tap Media & Purchases, then tap View Account. You might be asked to sign in with your Apple ID.
4. Tap Manage Payments.
5. Tap Add Payment Method.
6. Enter all needed payment method details, then tap Done.