ShowWindow(Application.Handle,SW_HIDE);

With Application Do SetWindowLong(Handle,GWL_STYLE,GetWindowLong(Handle,GWL_STYLE) and not WS_EX_APPWINDOW);

procedure TForm1.FormCreate(Sender: TObject);

begin

SetWindowLong(Application.Handle,GWL_EXSTYLE,GetWindowLong(Application.Handle,GWL_EXSTYLE) or WS_EX_TOOLWINDOW);

end;