Where do I find my Apple MC card number and expiration date?

See the following from How to find your Apple Card number - Apple Support

Find your Apple Card number, security code, and expiration date

To make purchases with Apple Card where Apple Pay is not yet accepted online, you can find your Apple Card number on your iPhone or iPad.

On iPhone

1. Open the Wallet app and tap Apple Card.
2. Tap the more button .
3. Tap Card Information, then authenticate with Face ID, Touch ID, or your passcode.
4. Next to Card Number, you can see your Apple Card number.

You can also see the last four digits of your Physical Card number and your Device Account Number.

On your iPad

1. Open the Settings App.
2. Scroll down and tap Wallet & Apple Pay.
3. Tap Apple Card, then tap the Info tab.
4. Tap Card Information, then authenticate with Face ID, Touch ID, or your passcode.