How to find the DFF column Names:

select distinct
fdfc.application_column_name attribute_no,
fdfc.end_user_column_name column1,
fdf.title,
fdfc.descriptive_flex_context_code dff_code,
fdf.application_table_name,
fdfc.display_flag Displayed,
fdfc.enabled_flag Enabled,
fdfc.required_flag Required1
from
apps.fnd_descriptive_flexs_vl fdf,
apps.fnd_descr_flex_col_usage_vl fdfc
where 1=1
and fdf.descriptive_flexfield_name=fdfc.descriptive_flexfield_name
and fdf.title like '%Vendor%Sites%'
---and fdf.descriptive_flexfield_name like '%PER_PEOPLE%'
and FDFC.DESCRIPTIVE_FLEX_CONTEXT_CODE='11565'
and FDFC.ENABLED_FLAG = 'Y'
---and fdfc.end_user_column_name like '%APPROVAL%STATUS%'
---order by FDFC.LAST_UPDATE_DATE desc