Hi, is it possible to save customers' confidential data when they make purchases not only through cryptocurrencies, but for example by card. What payment provider to choose for this task or what to do?
You mean you want for your customers to go through KYC? I'm not sure about card payments but for bitcoin, BitPay should have that.
You're probably not going to get hold of any data though, everything is done through a third party. But why would you want that anyway?