How do I pay with money on Apple ID to Apple Pay

You can't transfer money from your Apple ID to Apple Pay.

Contact iTunes Support for assistance. See the Apple Support articles below for contact information.   

iTunes Support – world wide 

Apple Support schedule phone call     

Billings and Subscriptions 

If necessary, try Twitter

https://twitter.com/AppleSupport.          People have posted it may take an hour or more to get a response.

Howdy Carats3,

It sounds like you want to know how to use Apple Pay. We know how important this is for you, and you’re in the right place to find a resolution.

Here's a resource and steps that can help:

• How to use Apple Pay

Take Care!

You are welcome.