Apple pay requires to update the .plist files and add the Merchant IDs created on apple developer console.

This plugin will help to edit .plist file for apple pay.

<!-- example for updates to config.xml -->
<platform name="ios">
  <!-- other properties here -->
  <config-file target="*-Debug.plist" parent="com.apple.developer.in-app-payments">
    <array>
      <string>Put your debug / developer merchant ID here</string>
    </array>
  </config-file>

  <config-file target="*-Release.plist" parent="com.apple.developer.in-app-payments">
    <array>
      <string>Put your production merchant ID here</string>
    </array>
  </config-file>
</platform>