[Grim_]

few errors there :P

pawn Код:

new cmd[256], idx;
cmd = strtok(cmdtext, idx);
if(strcmp(cmd, "/ban", true) == 0)
{ 
  if(PlayerInfo[playerid][PL1A] != 1) return SendClientMessage(playerid, color, "Not allowed to use this command!");
  new tmp[256];
  tmp = strtok(cmdtext, idx);
  if(!strlen(tmp)) return SendClientMessage(playerid, color, "Usage: /ban [id]");
  new targetid = strval(tmp);
  if(!IsPlayerConnected(targetid)) return SendClientMessage(playerid, color, "Invalid ID");
  new str[128], name[24];
  GetPlayerName(targetid, name, MAX_PLAYER_NAME);
  format(str, sizeof str, "%s has been banned by an administrator!", name);
  SendClientMessageToAll(color, "============================");
  SendClientMessageToAll(color, str);
  SendClientMessageToAll(color, "============================");
  return 1;
}

Something like this.
NOTE: Requires strtok, can be found here: https://sampwiki.blast.hk/wiki/strtok