The reason why it cannot be added is that Apple has not pushed it immediately. You can set the region to the United States and it should be able to be added.

The method of adding is as follows:

1. Click on the home screen to open the "Settings" application, as shown in the figure below:

2. Find it in the settings list In the "General" column, click to enter, as shown below:

3. Find the "Language and Region" column in the general list, click to enter, and click on the "Region" column, as shown in the following figure:

4. In the region list, select the United States, as shown below:

5. Return to the home screen and open the Passbook app, as shown in the picture:

6. In Passbook, you can see an additional "Set up Apple Pay" option, as shown below:

7. Click the "Add a new credit or debit card" column, as shown below:

8. Enter the credit card information, or you can use the camera to obtain the information on the card, as shown below:

9. If the bank card supports Apple Pay, it can pass the verification.