Many2one

python :

class LotNumber(models.Model):
 _inherit = 'account.move.line'

    lot_id = fields.Many2one(comodel_name='stock.production.lot', string='Lot/Serial Number', domain="[('product_id', '=', product_id), ('company_id', '=', company_id)]",check_company=True)



 XML :

 <record id="account_move_lot_number_invoice_inherit" model="ir.ui.view">
        <field name="name">account.move.lot.number.invoice.inherit</field>
        <field name="model">account.move</field>
        <field name="inherit_id" ref="account.view_move_form"/>
        <field name="arch" type="xml">
            <xpath expr="//field[@name='invoice_line_ids']/tree/field[@name='name']" position="after">
                <field name="lot_id" force_save="1"/>
            </xpath>
        </field>
  </record>