How do I stop a billing for an app. ?

Stop charging my credit card for the adult coloring book I no longer use them !

This is a user to user forum. You are not talking to Apple. As users we are not charging you for anything, nor can we stop the chargers either.

Only you can stop the charges, by cancelling the subscription. Don't expect anybody else to do it for you.

You can follow the steps in the support document linked above, to cancel your subscriptions.

Here it is again:

Link: View, change, or cancel your subscriptions - Apple Support

from iOS

Change or remove your Apple ID payment information - Apple Support

From OS X

Change or remove your Apple ID payment information - Apple Support

Apps are a single purchase only. iTunes itself is free of charge.

Some Apps may offer in App purchases and / or recurring subscriptions.

If the App in question offers a recurring subscription, then you deal with that by cancelling the subscription.

If it was an in-app purchase then its a one time thing each time. The only to stop the charges, is to stop performing in-app purchases.

You can login in to http://reportaproblem.apple.com to see a listing of your most recent purchases / charges and identify whether it a subscription or an in-app purchase.

If a subscription, follow this support document to cancel it.

View, change, or cancel your subscriptions - Apple Support

Stop charging my credit card for the adult coloring book I no longer use them !