How to make a map for my openworld game ?!

my game is open world.
player can drive in the city and get passenger to their destination.
now i want to make a map for my game.
what is the best way ?
i made my map and it can show player position.
but i want to show passenger position that gamer can understand where is passenger to get it.
please help me.

Okay if you want a driving game, you want a flat map with straight inclines, so Unity terrain isn’t your best choice. I recommend Maya and/or 3DS Max for the roads and assets and Trimble Sketchup for the buildings.

I don’t understand your second question.