procedure TForm1.Button1Click(Sender: TObject); 
begin 
  TForm2.Create(Application).Show; // Jangan simpan ke var global bawaan: Form2
end; 
procedure TForm2.Button1Click(Sender: TObject); 
begin 
  Self.Free; // Destroy diri sendiri, bukan spesifik ke instance tertentu; misal yg tersimpan di Form2 
end;

unit unit1;
type
  TForm1 = class(TForm)
    a: Tbutton;
    b: Tbutton;
    ........
    ........
    ........
  private

  public
     //biar gampang taruh referensi form lain disini, misalnya form 2 atao 3 sebanyak yang kita mau
    refLain_1 : TForm; // ini di typecast ke model TForm (biar ga bingung dan ga usah pake uses di bagian interface)
    refLain_2 : TForm;
    refLain_3 : TForm;
    refLain_4 : TForm;
    refLain_5 : TForm;
    refLain_6 : TForm;
    ........
    ........
    ........
    ........
  end;
var
  Form1: TForm1;
implementation
uses unit2, unit3, unit4, unit5;//jangan lupa dikasih uses buat form-form lain yang kita punya
    ........
    ........
    ........
    ........
procedure TForm1.aClick(Sender: TObject);
begin
   //misalkan kita punya tipe TForm2, TForm3, TForm4, TForm5
  //6 referensi form yang udah dideklarasikan diatas mau dibuat semuanya dengan variasi sembarang
  
  refLain_1:=TForm4.create(nil);
  refLain_2:=TForm2.create(nil);
  refLain_3:=TForm5.create(nil);
  refLain_4:=TForm5.create(nil);
  refLain_5:=TForm3.create(nil);
  refLain_6:=TForm2.create(nil);
  //dari situ kelihatan kalo aku bikin 2 form tipe TForm2, 2 form tipe TForm5, 1 form tipe TForm3. 1 form tipe TForm4.
 //nah terus misalkan setiap form di perlihatkan pake visible dan atribut lainnya misalnya:
  refLain_1.visible:=true;
  refLain_2.visible:=true;
  refLain_3.visible:=true;
  refLain_4.visible:=true;
  refLain_5.visible:=true;
  refLain_6.visible:=true;
end;

    ........
    ........
    ........
    ........
end.

=======================================================
//INI FORM 2 MISALNYA
unit unit2;
...
...
type
  TForm2 = class(TForm)
    c: Tbutton;
    d: Tbutton;
  private
  public
  end;

implementation
//disini dikasih uses (BIAR BISA AKSES KE MAIN FORM)
uses  
   unit1, unit3, ... , ... , ... ;
procedure TForm2.cClick(Sender: TObject);
begin
   //disini kita bias mainkan variable- variable referensi form dari form1, entah mau diubah visibility nya, ato mau dihancurkan
   //asalkan hati hati sebaiknya jangan  menghancurkan form diri sendiri :D 
  form1.refLain_1.free;
  form1.refLain_3.free;
  form1.refLain_4.free;
 ....
 ....
  
end;
end.

var
  list: TStringList;
implemetation
function  GetForm(nama_form: string): TForm;
var
  int : Integer;
begin
  result := nil;
  int := list.IndexOf(nama_form);
  if int < 0 then exit;
  result := TForm(list.Objects[int]);
end;
function  AddForm(nama_form): TForm;
begin
  result := TForm.Create(nil);
  list.AddObject(nama_form, TObject(result));
end;
procedure  ShowForm(nama_form);
var
  form : TForm;
begin
  form := GetForm(nama_form);
  if form = nil then exit;
  form.Show; // or form.ShowModal;  
end;
procedure  CloseForm(nama_form);
var
  form : TForm;
begin
  form := GetForm(nama_form);
  if form = nil then exit;
  form.Close;
end;
procedure RemoveForm(nama_form: string);
var
  int : Integer;
begin
  int := list.IndexOf(nama_form);
  if int < 0 then exit;
  TForm(list.Objects[int]).Free;
  lst.Delete[int];
end;

initialization
  list:= TStringList.Create;
finaslization
  list.Free;