I have tried to add apple card to wallet on my Macbook Pro, but i cannot add it. I don't know why.

Add Apple Card to your Mac

1. Update to the latest version of macOS. 
2. Go to System Preferences, then select Wallet & Apple Pay.
3. Click the plus button (+).
4. Select Apple Card, then choose Next and follow the steps on your screen.

You can make Apple Card your default card on your Mac. This makes Apple Card your default card when you use Apple pay on your Mac.

To add Apple Card to Wallet, you need a Mac model with Touch ID. If you have a Mac model without built-in Touch ID, you can turn on Allow Payments on Mac to complete your purchases on your eligible iPhone or Apple Watch:

On your iPhone, open the Settings app, tap Wallet & Apple Pay, then turn on Allow Payments on Mac.

Is your Apple Card active on your iPhone?