Excuse me, Umberto. If I want the choose service on the ground by Alitalia or, for example by ADR of Rome, which setting I have to set?
As explained several times on the forum, the operator choice menu will display all operators that have full ICAO matching, meaning 4 letters of the ICAO code matching their Icaoprefixes codes.
You don't say which airport you are referring to so, assuming it's LIRF, since only ADR has a 4 letter match, there will be no choice menu (no need to display a menu, when there's only 1 choice), and this of course is correct, since ADR is the one and only ground operator at LIRF, which is why is has been set like that.
If you want to add other operators, you need to change all the sim.cfg vehicles. The PaintKit documentation explains how to do this, so there's no need to repeat it here.
Besides, is it possible for me track the way for passenger bus?
I don't understand you, please clarify.