What happens if I want to lock my card?

You can access the settings through Card & Account, which allows you to lock the card from both digital and physical usage.

What happens if I want to report my card stolen or terminate it?

You can access the settings through Card & Account, which allows you to terminate the card. At that point, a new Digital card is created and available in the app. You will also receive information on how to order a new physical card.

Can I just terminate my physical card and keep the digital card the same?

No, since the details are the same, terminating one will terminate both. In this case, you would need to add new details to online merchants and re-provision with Apple/Google.