How do I delete old cards. Also how can I change phone number

To find out how to remove a payment method, and what to do if you can't remove your last payment method or use no payment method with your Apple ID, read this article --> Remove a payment method from your Apple ID - Apple Support

Ongoing subscriptions and Family Sharing organizers must always have a payment method present. To edit the cards used for those you may need to first add the new card and make it the primary payment method before removing the old card (see: If you need to change or update your Apple ID payment method - Apple Support ).

To edit your list of trusted items go to the section: About trusted phone numbers and trusted devices in the document Two-factor authentication for Apple ID - Apple Support

To see, add, or change your trusted phone numbers:

- On your iPhone, iPad, or iPod touch: Go to Settings > your name > Password & Security. Next to Trusted Phone Number, tap Edit.

- On a Mac: Choose Apple menu  > System Settings (or System Preferences), then click your name (or Apple ID). Click Password & Security, then add or remove a trusted phone number.

- In a web browser: Go to the Account Security section of https://appleid.apple.com/