public void SaveAccount(ParentModel objAccountModel)
    {
        using (OrganizationService service = new OrganizationService("MyConnectionString"))
        {
            Guid? accountid = null;

            if (objAccountModel != null)
            {
                Entity accEntity = new Entity("account");
                accEntity["name"] = objAccountModel.Customer.Company;

                accountid = service.Create(accEntity);

            }

        }
   }

<add name="MyConnectionString" connectionString="Url=https://makeademo.crm.dynamics.com; Username=asin@makeademo.onmicrosoft.com; Password=aaaaa;" />