can someone suggest a website where we can see realtime implementation of Folio

Can someone suggest a website where we can see realtime implementation of Folio (not a demo website).

There are “live” FOLIO demo sites that you can interact with and test. If you are asking about production FOLIO sites, running in real libraries, then they do not exist yet, as nobody is running FOLIO in production yet (as far as we know!).

So does that mean that Folio is not installed in any library till now and it is still in testing /development phase?

Yes, that is correct. There are libraries that are working with FOLIO with test migrations of their own data, but none are in production.