if(GetPlayerState(playerid) == PLAYER_STATE_DRIVER) //checks if player is in a vehicle
{
    new vehicleid = GetPlayerVehicleID(playerid); //declares a variable and sets it to the players vehicles id
    SetVehiclePos(vehicleid, 123.4567, 123.4567, 123.4567); //changes vehicles position
    SetVehicleZAngle(vehicleid, 234.5678); //sets vehicles angle
    PutPlayerInVehicle(playerid, vehicleid, 0); //puts the player in vehicles driver seat
}