How to show drawer below AppBar

Wrap your main Scaffold in another Scaffold and use the drawer of child Scaffold also make sure to set automaticallyImplyLeading to false so you don't get back icon in the AppBar

UPDATE : i don't recommend this way because of this issue

return Scaffold(
      primary: true,
      appBar: AppBar(
        title: Text("Parent Scaffold"),
        automaticallyImplyLeading: false,
      ),
      body: Scaffold(
        drawer: Drawer(),
      ),
    );

Final Result :