Q: How to edit a card on Apple Pay - new expiration date and security code

Remove & Re-add.

There have been a few posts that suggest that the information is updated automatically.

My TD bank debit card did not get its expiration date updated automatically, I had a transaction declined and the TD help desk confirmed it was a card expiration date problem. My card had been replaced recently on the normal 3-year cycle.

Well, now it seems as if it's up to the financial institution to determine if they will automatically update the expiration date.  Regions Bank does update the expiration date based on a FAQ that someone linked to in a different post.

Amex also can update Apple Pay information as they changed my partners card number after they issued a new number because the card was left at a merchant location (card was found, we opted to have Amex issue a new number anyway).  They even sent an email saying the information was updated in Apple Pay.

Since my bank doesn't automatically update the expiration date, I removed the old card, then added the new card with new expiration date.