How do I remove a card from Apple pay ?

You can only remove a card, if you have another card as a valid form of payment. Assuming you do have another card on file with your Apple Account, on your iPhone, open the Settings App and scan down to Wallet & Apple Pay.

Then follow these directions:

1. In the Wallet app, tap the card that you want to remove.
2. Tap the More button, then tap Card Details.*
3. Scroll down and tap Remove Card.

Is the card in your Apple ID Account or your Apple Wallet? Cards can easily be removed from Apple Wallet, but as lobsterghost1 posted, Apple ID Account may require a payment method.

So, where is your card?