[Karsh]

можно и так:

Код:

procedure TForm1.Button1Click(Sender: TObject);
var
  myFile: TextFile;
begin
  AssignFile(myFile, 'myfile.txt');
  Rewrite(myFile);
  try
    Writeln(myFile, 'Строка 1');
    Writeln(myFile, 'Строка 2');
  finally
    CloseFile(myFile);
  end;
end;