Could not really understand your question fully.
Based on what ever I could understand:
- If you want to capture the type of the document for every document being uploaded, you can add a specialized entity for FileDocument like for example: AgeProof
- In that entity, you can add a new field of type ENUM and define all your document types there
- When User is uploading the document, make the Document type field mandatory so, it will be filled by user
If the above does not answer your question, then please re-phrase your question in proper English so everyone can understand.
Yes, as mentioned, you may use Enumeration to specify the documents.