[ifly4life]

SetVehicleNumberPlate(vehicleid,"NAME");
Try this or below to make the plate ther persons name:
Pawn Code:
public OnPlayerStateChange(playerid, newstate, oldstate)
{
new vehicleid;
vehicleid = GetPlayerVehicleID(playerid);
new plname[24];
GetPlayerName(playerid, plname, sizeof(plname));
if(GetPlayerState(playerid) == PLAYER_STATE_DRIVER)
{
SetVehicleNumberPlate(vehicleid,plname);
return 1;
}
return 0;
}