To install account module and searching by name in account module in customers invoice form and get results in particular name use this code in account_invoice file in account module in openerp.

Code given below:-

def name_search(self, cr, user, name, args=None, operator='ilike', context=None, limit=100):
        if not args:
            args = []
        if context is None:
            context = {}
        ids = []
        if name:
            ids = self.search(cr, user, [('number','=',name)] + args, limit=limit, context=context)
        if not ids:
            ids = self.search(cr, user, [('name',operator,name)] + args, limit=limit, context=context)
        return self.name_get(cr, user, ids, context)