My family manager is on an old iPad that is no longer usable

The Family Sharing Organizer is a person, not a device. The Organizer will have to either find equipment where they can use their account and edit payment information, or add a new payment method online at http://appleid.apple.com/

If using Family Sharing as stated, all payments/charges are made against the Family Organiser’s registered payment method(s) - and only the Family Organiser can update or change the payment methods.

You must always have at least one payment method registered with your AppleID account - against which any Apps, Media or Subscription services that are purchased from Apple will be charged.

A registered payment method cannot be modified, but can be deleted. If you only have one registered payment method, you must add another before the existing entry can be removed from the AppleID account.

You may find these support pages to be helpful:

If you need to change or update your Apple ID payment method - Apple Support

Add a payment method to your Apple ID - Apple Support

Remove a payment method from your Apple ID - Apple Support

Payment methods that you can use with your Apple ID - Apple Support

I am confused. Are you the Organizer? If you are not, you cannot edit payment information for the Organizer. If you are then this document explains how to add a payment method to your Apple ID on a Mac, Apple mobile devices, PC, or online. Click here --> Add a payment method to your Apple ID - Apple Support

julianne31 wrote:

Okey dokey! But what if you deleted the first payment? How do I go back and add a new payment?

To be clear, only the Family Organiser can update the registered payment method. If the Organiser doesn’t have a device that is signed-in to the Family Organiser’s AppleID, the Organiser can manage their account and associated payment methods using a web browser*:

https://appleid.apple.com

Once signed-in, the Organiser can manage/add/delete registered payment methods. Remember, you must add a new valid payment method before the one remaining (presumed now invalid) payment method can be deleted from the account.

(*) The Family Organiser will need to satisfy the two-factor authentication challenge to access the account from a web browser - either responding to the challenge from a trusted device, or choosing one if the available pre-configured alternatives.

Change the Apple Id