[[Io]]

Como una imagen vale más que mil palabras...

Código Delphi [-]
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}
uses unit2;

procedure TForm1.Button1Click(Sender: TObject);
begin
  with TForm2.Create(self) do
  begin
    parent:=self;
    show;
  end;
end;

end.

Código Delphi [-]
unit Unit2;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm2 = class(TForm)
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form2: TForm2;

implementation

{$R *.dfm}

procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  action:=caFree;
end;

end.

Haber si ha suerte y me dices dónde me he equivocado.

Adjunto el ejemplo, que por cierto me da un error al compilar, me sale la ventana CPU y no lo sé interpretar.
Saludos