Target Player anywhere ?
 

Hi, sorry for my english and thanks to answer/s.
It can be, so I will focus a player anywhere?

I think you can use either /target or /targetexact. There are limits, like they have to be in visual range. I don't think you can target enemy players this way, but I could be wrong. You can try the same with /focus, but remember that when they go out of visual range, your focus may be lost and would need to be set again.

A focus/target through the friends list is possible?

Not trough friend list, it would still /target them by name.