[Lajko1]

first you can use

pawn Code:

public OnGameModeInit()
{
    EnableZoneNames(1);
    return 1;
}

Secondly you can do

pawn Code:

stock IsPlayerInArea(playerid, Float:max_x, Float:min_x, Float:max_y, Float:min_y)
{
new Float:X, Float:Y, Float:Z;
GetPlayerPos(playerid, X, Y, Z);
if(X <= max_x && X >= min_x && Y <= max_y && Y >= min_y) return 1;
return 0;
}

All you need is to set coordinates to one you wish

and at end just check if players is in zone it will send GameTextForPlayer or textdraw or smth to player with message you wish.