curl --request GET \
  --url https://api.e-invoice.be/api/documents/{document_id}/ubl \
  --header 'Authorization: Bearer <token>'

{
  "file_name": "<string>",
  "id": "<string>",
  "file_size": 0,
  "signed_url": "<string>",
  "sender_peppol_id": "<string>",
  "sender_peppol_scheme": "<string>",
  "receiver_peppol_id": "<string>",
  "receiver_peppol_scheme": "<string>",
  "file_hash": "<string>",
  "validated_at": "2023-11-07T05:31:56Z"
}