Code:

unit Unit2;

interface

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

type

TForm2 = class(TForm)

private

{Private declarations}

public

   constructor CreateWithCaption(aOwner: TComponent; aCaption: string);

{Public declarations}

end;

var

Form2: TForm2;

implementation

{$R *.DFM}

constructor TForm2.CreateWithCaption(aOwner: TComponent; aCaption: string);

begin

Create(aOwner);

Caption := aCaption;

end;

uses Unit2;

procedure TForm1.Button1Click(Sender: TObject);

begin

Unit2.Form2 := Unit2.TForm2.CreateWithCaption(Application, 'My Caption');

Unit2.Form2.Show;

end;