unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;

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

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
 var notepad, edit: HWND;
begin
   notepad := FindWindow('notepad', nil);


  PostMessage(notepad, WM_KEYDOWN, VK_F5, 0);
PostMessage(notepad, WM_KEYUP, VK_F5, 0);
end;

end.