1)rental product send by sale order then create invoice 2)use contract management it will generate invoice automatically 3)use Rental module try one of them

thank you

I found the solution for this query if any one of you get stuck in such case please follow the below steps.
Go to Administration->Scheduler->Scheduled Actions->Rent - Invoices Crone to change this.
File name:-rental.py

def _prepare_order_picking_rent_in(
            self, cr, uid, order, date, context=None):
        return {
            'name': self.pool['ir.sequence'].get(cr, uid, 'stock.picking.in'),
            'origin': order.name,
            'date': self.date_to_datetime(cr, uid, date, context),
            'type': 'in',
            'state': 'auto',
            'move_type': order.picking_policy,
            'sale_id': order.id,
            'partner_id': order.partner_shipping_id.id,
            'note': order.note,
            'invoice_state': 'Auto',
            'company_id': order.company_id.id,
}

def _prepare_rental(self, cr, uid, line, out_move_id, context=None):
return {
'start_order_line_id': line.id,
'out_move_id': out_move_id,
}