Why I’m not allowed to use my Apple ID balance?? Pls I need to purchase

This document outlines what you can buy with your Apple ID [Apple Account] balance --> What you can buy with your Apple Gift Card or Apple Account balance - Apple Support

"Some purchases might require that you have a credit card on file, even if you use your Apple Account balance to make the purchase."

"Where the Apple Gift Card is available, you can use your Apple ID balance to buy products and accessories at apple.com or in the Apple Store app."

How apps, content, and subscriptions from Apple are billed - Apple Support

Some purchases aren’t charged to your Apple Account balance

- If you're in a Family Sharing group, purchases that you make are charged to your personal Apple Account balance. If you don't have enough Apple Account balance to pay for the purchase, the remainder is charged to the family organizer if purchase sharing is turned on.

- You can’t use your Apple Account balance to buy gifts or gift cards.

- Some subscriptions might not be charged to your Apple Account balance.

Some people also confuse a message requiring they enter a payment method as meaning they cannot use their account balance.I only have completely free apps. I know I personally can download and update these apps without having a payment method, or even any account balance. However, Apple has multiple criteria requiring the presence of a payment method. If you are encountering one of those situations, you have no option but to enter a valid payment method if you wish to continue downloading. Read the support article Add a payment method to your Apple ID - Apple Support about how to do that. The payment method may not be charged if you also have account balance, but the payment method has to be present. This next article lists valid payment methods for different countries but note that in this case Apple Account balance alone apparently does not meet the requirement: Payment methods that you can use with your Apple ID - Apple Support .