var
  myini :TIniFile;

procedure TForm1.FormCreate(Sender: TObject);
begin
  myini := TIniFile.Create('C:\123.ini');
  Edit1.Text := myini.ReadString('MySection', 'MyIdent', 'It is default text')
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  myini.WriteString('MySection', 'MyIdent', Edit1.Text);
  myini.Destroy;
end;