change credit card for icloud storage payment

iCloud uses the payment methods added to your Apple ID in the order the appear in.

Follow the steps in the support document linked below to add a new payment method and set it at the top to be used first.

click here ➜ Add a payment method to your Apple ID - Apple Support

Visit appleid.apple.com to update payment

There is no distinction between the payment method for your iCloud+ plan, and other products and services for which you may have to pay as linked to your Apple ID. They all use the same payment method. I suppose you could make a different payment method ‘primary’ at certain dates of the month, but that is tedious and prone to manual errors.