Apple Cash

I’ve just had to restart my phone and in my settings there’s an option where I can set up Apple Cash however I’m from the UK so I don’t understand why there’s an option and then when I click it is asking me for the SSN number using the US funny enough I literally literally just come back from America on vacation so might have set up on that end without me knowing is that available in the UK or is it just in the US that’s available someone help me out please thank you