In traceability fields first we have to go in .py file (Python file) After that we have to decide where we want traceability fields and then give start to end Path to that field.Use below .py code in python file:

'date': fields.date('Entry Date', required=True, readonly=True),
        'user_id': fields.many2one('res.users','User', readonly=True),
        'update_date': fields.date('Update Date',readonly=True),
        'update_by': fields.many2one('res.users', 'Updated by', readonly=True),        
    }
    _defaults = {
        'type': _get_type,
        'state': 'draft',
        'day_count_basis': '360',
        'date': lambda *a: time.strftime('%Y-%m-%d'),
        'user_id': lambda self,cr,uid,context: uid,
        'company_id': lambda s,cr,uid,c: s.pool.get('res.company')._company_default_get(cr, uid, 'account.coda', context=c),
    }        

    def onchange_date(self, cr, uid, ids, date_start, date_stop):
        if not (date_start and date_stop):
            return {}
        res = {}
        date_start = datetime.strptime(date_start, '%Y-%m-%d').date()
        date_stop = datetime.strptime(date_stop, '%Y-%m-%d').date()
        nbr_days = (date_stop - date_start).days
        if nbr_days < 1 :
            raise osv.except_osv(_('Error!'), _('Invalid Date Range!'))
            return {}
        return {'value':{'days': nbr_days}}

    def button_confirm(self, cr, uid, ids, context=None):   
        if context is None:
            context = {}
        seq_obj = self.pool.get('ir.sequence')
        seq_sl_code = 'account.straight.loan.demand'
        seq_pl_code = 'account.placement.demand'
        cfpline_obj = self.pool.get('account.cashflow.provision.line')
        for demand in self.browse(cr, uid, ids, context=context):
            # amount_main provision
            cfpline_obj.create(cr, uid, {
                'origin': demand._name + ',' + str(demand.id),
                'description': (demand.description and (demand.description + ' - ') or '') + _('Transaction Amount'),
                'state': 'confirm',
                'journal_id': demand.journal_id.id,
                'val_date': demand.date_start,  
                'amount': demand.type == 'loan' and demand.amount_main or -demand.amount_main,
                'cashflow_code_id': demand.cfc_id_main_start.id,
                }, context=context)
            cfpline_obj.create(cr, uid, {
                'origin': demand._name + ',' + str(demand.id),
                'description': (demand.description and (demand.description + ' - ') or '') + _('Transaction Amount'),
                'state': 'confirm',
                'journal_id': demand.journal_id.id,
                'val_date': demand.date_stop,  
                'amount': demand.type == 'loan' and -demand.amount_main or demand.amount_main,
                'cashflow_code_id': demand.cfc_id_main_stop.id,
                }, context=context)