Hi Sdji1950,
Welcome to the Apple (user-to-user) Community.
Your Apple ID is the account that you use to access all Apple services and make all of your devices work together seamlessly.
Make sure you are signed in (to your iPhone) with your Apple ID.
Sign in with your Apple ID - Apple Support
Apple support have articles online (links below) that may guide you:
You may need to add a new card / Apple ID payment method first:
See if Apple support's method works for you:
How to: Add a payment method to your Apple ID - Apple Support
How to: Remove a payment method from your Apple ID - Apple Support
or
If you need to change or update your Apple ID payment method – Apple Support
If needed:
Apple ID Support:
Apple ID - Official Apple Support
All the best :-)