Would like to add my Visa card please help me

See this link —>https://support.apple.com/en-us/HT201266

I've tried to add my Chase Visa from my PC and declined. Then from my iPhone 7, and I see "This payment method can't be used with the iTunes Store. Try again using another payment method." There is also reference to "your wallet". What have I done wrong, and what the heck is a wallet--as defined by Apple, as the Visa card is most definitely in MY wallet! :-)

Is your credit card issued in the country of the region you are tied to in App Store? If it is, you need to contact iTunes support for assistance with payment methods. Use the Contact Support button at the top of this page.