procedure TForm2.Button1Click(Sender: TObject);
var
notepad, edit: HWND;
i: integer;
s: string;
begin
notepad := FindWindow('notepad', nil);
edit := FindWindowEx(notepad, FindWindow('Edit', nil), nil, nil);
s := Edit1.Text;
for i := 1 to Length(s) do
SendMessage(edit, WM_CHAR, dword(s[i]), 0);
end;