[Retardedwolf]

You need to search and wiki.

pawn Код:

public OnPlayerConnect(playerid)
{
  new string[64], pName[MAX_PLAYER_NAME];
  GetPlayerName(playerid,pName,MAX_PLAYER_NAME);
  format(string,sizeof string,"%s has joined the server. Welcome!",pName);
  SendClientMessageToAll(0xFFFFFFAA,string);
  return 1;
}

https://sampwiki.blast.hk/wiki/OnPlayerConnect