General info on how to add Apple,Card into Wallet:
How to add Apple Card to your Apple devices - Apple Support
Here’s the troubleshooting info:
If you have trouble adding Apple Card to a new device
- Make sure that you're signed into the device with the same Apple ID that you used to apply for Apple Card.
- Make sure your device has a good internet connection.
- Make sure the Settings app and Wallet app are enabled for cellular data:
- Open the Settings app on your iPhone or iPad.
- Tap Cellular.
- Turn on Cellular Data.
If you need help adding Apple Card to your devices, contact Apple Support.
If not already familiar, Wallet is the app you would want to use here. General info:
How to use Wallet on your iPhone, iPod touch, and Apple Watch - Apple Support