Why is the Original Source section is not visible after Make a Copy?
Vault allows the reuse of documents or binders with the Make a Copy option. The new object can duplicate the fields, content, structure, or relationships of the original document. A relationship is created between the source object and its copies to allow for traceability.
An Admin can enable this feature in Admin --> Settings --> General Settings by selecting the Enable Original Source Tracking checkbox. When enabled, all existing documents have the Original Source relationship applied where applicable.
Vault Help Documentation: Tracking Source & Copy Relationships