[AlTy]

pawn Code:

CMD:a(playerid, params[]){
    if(PlayerInfo[playerid][pAdmin] < 1) return 0;
    if(sscanf(params,"u", strings)) return SendClientMessage(playerid,COLOR_LIGHTBLUE, "USAGE: {FFFFFF}/a [text]");
    new Name[MAX_PLAYER_NAME];
    GetPlayerName(playerid, Name, sizeof(Name));
    format(strings, sizeof(strings), "Admin %s: %s", params, name);
    SendClientMessageToAll(0x1874CDAA, strings);
    return 1;
}

^^ version with name

EDIT: NVM u all too fast.