效果图

新建窗体

窗体的显现

procedure TForm2.btn2Click(Sender: TObject);
begin
  Form1.Show;
  Form2.Hide;
end;

第一个窗体完整代码

注意引用第二个窗体

unit Unit1;

interface

uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Dialogs, Forms,Form, Formprpt, StdCtrls;

type
  TForm1 = class(MForm)
    lbl1: TLabel;
    lbl2: TLabel;
    lbl3: TLabel;
    edt1: TEdit;
    edt2: TEdit;
    edt3: TEdit;
    btn1: TButton;
    procedure btn1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

uses Unit2;  //要加这个

{$R *.DFM}

procedure TForm1.btn1Click(Sender: TObject);
begin
  //主窗体隐藏，第二个窗体显示
  form1.Hide;
  form2.show;
  //展示输入的数据
  Form2.lbl1.Caption:='您的姓名：'+edt1.Text;
  Form2.lbl2.Caption:='所购商品：'+edt2.Text;
  Form2.lbl3.Caption:='商品数量：'+edt3.Text;
end;

end.

第二个窗体完整代码

注意引用第一个窗体

unit Unit2;

interface

uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Dialogs, Forms,Form, Formprpt, StdCtrls;

type
  TForm2 = class(MForm)
    lbl1: TLabel;
    lbl2: TLabel;
    lbl3: TLabel;
    btn1: TButton;
    btn2: TButton;
    procedure btn1Click(Sender: TObject);
    procedure btn2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form2: TForm2;

implementation

uses Unit1;  // 引用第一个窗体

{$R *.DFM}

procedure TForm2.btn1Click(Sender: TObject);
begin
  form1.close;
  Form2.Close;
end;

procedure TForm2.btn2Click(Sender: TObject);
begin
  Form1.Show;
  Form2.Hide;
  form1.edt1.Text:='';
  form1.edt2.Text:='';
  form1.edt3.Text:='';
end;

end.