can some one help me with this?
On browser you can look at the URL. It will start with "US" followed by a number which indicates the server (world) you are currently on.
I think on mobile the on only way is to exit and go back in.
If you have been active long enough to get picked up by Elvenstats,com, you can
search for your account name there: If you aren't there yet, you could look for a big neighbour who is active (you see them offering large trades in your trader, or they've been helping you) then search for them in Elvenstats. They don't update live, so you need to look for their score in your world, and see which one matches most closely. i.e., what I get there is this:
So if I were your neighbour, and had a score of about 461000, you'd know you were in Felyndral / US3