How I manage my payment to my device only

A payment is assigned to an Apple ID and is used for any place where you use that Apple ID. If you have a work related device and wish to use a different card then you will either need to enter a second card and move it to your primary payment method so charges go to that (and remember to change it back!), or set up a separate Apple ID and use that on your other device.

This document explains how to 'Change, add, or remove Apple ID payment methods' on an Apple mobile device, a Mac, or a PC; click here --> https://support.apple.com/HT201266

- Alter your primary payment method.

Create an Apple ID. Click here --> https://support.apple.com/HT204316

Remember, you are working within the confines of how payments are charged, which is automatic. You'll have to see which method of playing around best suits your habits:

How App Store and iTunes Store purchases are billed - https://support.apple.com/HT201359

"Which payment method is charged?

When you buy items or pay for subscriptions, Apple 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 or you don't have enough to cover the full amount, Apple attempts to charge your primary payment method. 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.

3. If there's a problem with the primary payment method, or if the primary payment method can't be charged for the full remaining amount, Apple attempts to charge your other payment methods in order from top to bottom. If none of them can be charged, Apple may try again.