send notification without using User model

How can I send a notification without having to use the user model?

   public function SendSeguimiento(Request $request){


   $toUser = Clientes::find(2);


    

   Notification::send($toUser, new Seguimiento($toUser));
    // $pageName = 'widgets';
    return redirect()->route("clientes");
}

i try to send a notification to the email of the table 'Clientes' in row 2

database:

Error:

help pls

via Chebli Mohamed