Need details for Document of Records

Summary:

Hi,

We have below queries on Document types or records: 

1.  Can modifications be made to existing document types delivered by Oracle? 
      - change description
      - change security
      - can we modify the country specificity
2.  When creating new document types, are we allowed to create new categories?
3.  Are we limited on the number of new categories if we need to create them?
4. For every new document type, can we add country specificity
5. Can we make fields with the document of records upload mandatory
6.  How many documents can we upload at one type - does it have to be all by specific type or can the upload include different types as long as they are identified?