If you think your titanium Apple Card was stolen, you first need to lock your card  

Say it wasn’t stolen, and you found your Apple Card after misplacing it

Now that you’re done locking your Apple Card, the next step is to request a new one.

If you already sent a request for your replacement card but found that your Apple Card has just been misplaced

If you’re using Apple Card Family, you can lock a participant’s titanium Apple Card if you’re the account owner or co-owner.

The process for unlocking a participant’s titanium card is similar to unlocking your own Apple Card.

Given that you're using the same Apple ID across all of your devices