Dear, samsung pay works with some selected banks credit or debit cards only. You can't use UPI with this samsung pay app. This app can literally work like a magnetic debit or credit card with a built in hardware. It's not like Google pay or paytm.
UPI is something developed by govt of India for unifying payments inside India. It connects between your bank accounts or mobile numbers. What samsung pay does is, it saves the card data in your phone and when ever necessary it can emulate a virtual magnetic card that can be used at any magnetic card readers. Samsung pay needs either an NFC reader or a magnetic reader to work. Simply, it needs to be in contact with a credit or debit card reader that we see in shops innorder to work.
