Use a different payment method for your iCloud subscription

You cannot use it for iCloud specifically unless you are very organized. You would have to make sure that you have no account balance and that you have multiple payment methods on your account. Move the one you want to use for iCloud to the top of the list when the subscription comes due and then move it down again if you have other payments to be made before the next time the subscription is due.

From this support article --> How apps, content, and subscriptions from Apple are billed - Apple Support

"Which payment method is charged?

When you buy items or pay for subscriptions, Apple automatically attempts to charge your payment methods in this order:

1. Apple attempts to use your Apple ID balance to cover the full amount.

2. If you don't have Apple ID balance, you don't have enough to cover the full amount, or an item cannot be paid for with Apple ID balance, Apple attempts to charge your primary payment method (typically a credit or debit card, but varies according to country). The primary payment method is at the top of the list in Settings on your iPhone. You can control which payment method is at the top of the list. [See: Add a payment method to your Apple Account - Apple Support ]

Here's how to change the payment method order for your Apple account after Apple account balance (which will be charged first in all cases unless the item you are buying cannot be charged to account balance). For the first four steps, refer to the first image in this Support article Add a payment method to your Apple Account - Apple Support where it says to tap Edit to reorder or remove a payment method.

1. Tap on the Settings app.

2. Tap on the Apple ID section at the top of the page (your name).

3. Tap Payment & Shipping (on old versions this is iTunes & App Store).

4. Tap Edit.

5. Tap and hold on your preferred Card and drag it up or down the list.

6. Tap Done.

You're welcome!