I can’t add card to my wallet because there is no add symbol on my wallet

Check your Apple ID region to make sure it is correct and make sure the region is correct on your device. Make sure you are using a passcode, Go to these links and make sure you follow the instructions on each one - Countries and regions that support Apple Pay - Apple Support

here too - If you can't add cards to Wallet for Apple Pay - Apple Support

did you read my response and go to the links I provided?

try signing out of your Apple ID on your phone and back in.