Organization  and Classifications Through API:

declare
l_validate_mode          BOOLEAN := TRUE;
l_begin_date             DATE    := SYSDATE;
l_end_date               DATE    := hr_general.end_of_time;
l_business_group_id      NUMBER  := 81;
l_orgname                hr_all_organization_units.name%TYPE := 'MTODEV TEST1';
l_intl_extl              fnd_lookup_values.meaning%TYPE :='INT';
l_organization_id        hr_all_organization_units.organization_id%TYPE;
l_object_version_number  hr_all_organization_units.object_version_number%TYPE;
l_duplicate_org_warning  BOOLEAN;
begin
  hr_organization_api.create_organization
  (
     p_effective_date              => l_begin_date --Reference date for validating lookup values
    ,p_business_group_id           => l_business_group_id
    ,p_date_from                   => l_begin_date --Date the organization takes effect
    ,p_name                        => l_orgname
    ,p_location_id                 => 142
    ,p_date_to                     => l_end_date
    ,p_internal_external_flag   => l_intl_extl--'INT' --Internal/External org flag
    ,p_internal_address_line   => null
    ,p_type                        => null  --Org type -- Lookup Type ORG_TYPE
    ,p_comments                    => null
    ,p_attribute_category          => null
    ,p_attribute1                    => null
    ,p_attribute2                    => null
    ,p_attribute3                    => null
    ,p_attribute4                    => null
    ,p_attribute5                    => null
    --Out Variables
    ,p_organization_id                 => l_organization_id
    ,p_object_version_number      => l_object_version_number
    ,p_duplicate_org_warning       => l_duplicate_org_warning
    );

   if l_organization_id is null or l_object_version_number is null then
      dbms_output.put_line('hr_organization_api.update_organization API Error: '||sqlerrm);
      rollback;
   elsif l_duplicate_org_warning then
      dbms_output.put_line('Warning: Duplicate Organization');
      rollback;
   else
      commit;
   end if;  
--
exception
  when others then
     dbms_output.put_line('hr_organization_api.create_organization API failed with error :'||sqlerrm);
     rollback;
end;

========================================================================================================

DECLARE
     l_validate_mode          BOOLEAN := TRUE;
     l_begin_date             DATE    := SYSDATE;
     -- Output Variables
     V_ORG_INFORMATION_ID            NUMBER;
     V_OBJECT_VERSION_NUMBER         NUMBER;
BEGIN
     --  Calling API HR_ORGANIZATION_API.CREATE_ORG_CLASSIFICATION
     hr_organization_api.create_org_classification(P_EFFECTIVE_DATE               => l_begin_date
                                                  ,P_ORGANIZATION_ID              => 169  --173
                                                  ,P_ORG_CLASSIF_CODE             => 'HR_ORG'  --'INV'
                                                  ,P_ORG_INFORMATION_ID           => V_ORG_INFORMATION_ID
                                                  ,P_OBJECT_VERSION_NUMBER        => V_OBJECT_VERSION_NUMBER
                                                  );

dbms_output.put_line(V_ORG_INFORMATION_ID);
COMMIT;
exception when others then
     dbms_output.put_line('error : ' || sqlerrm);
END;

P_ORG_CLASSIF_CODE we can get values from 

HR_LOOKUPS WHERE LOOKUP_TYPE ='ORG_CLASS'