Trouble with payment method

Hi nafeesah856,

Welcome to the Apple Community.

Wondering if the payment method is for your Apple ID account.

Your Apple ID is the account you use to access Apple services,

such as the App Store, iTunes, Apple Music, iCloud, iMessage, FaceTime and more.

Apple support have articles online that may help.

You might want to browse the articles, to choose what info. you need.

First: About Apple ID .... below about Apple Pay.

Payment methods that you can use with your Apple ID:

(Scroll down to find your country or region)

https://support.apple.com/en-au/HT202631

Change, Add or Remove Apple ID Payment methods

https://support.apple.com/en-us/HT201266

To add funds to your Apple ID balance, 

Use the payment method that you have on file:

https://support.apple.com/en-au/HT208687

what to do 

"If your payment method is declined in the App Store or iTunes Store”

https://support.apple.com/en-au/HT203005

For Apple Pay:

Scroll down to Add a card on your iPhone 

on this "Set-up" Page:

https://support.apple.com/en-au/HT204506

If you can't add cards to Wallet to use with Apple Pay

Get help adding cards:

https://support.apple.com/en-au/HT205630

Hope this helps you :-)