Hello Hameed,
the easiest way is probably a simple SQL Statement to get the info from your dwdata.
SELECT DOCTYPE FROM archive GROUP BY DOCTYPE
This should give back a list of all the values stored in the index field "DOCTYPE" from your archive. You can then export that list to excel, depending on what Software you use to access the database.
Greetings from Germany,
Simon H. Hellmann
DocuWare System Consultant