Parent documents are either the parent email to an email attachment or the parent document of an embedded document (such as an Excel spreadsheet embedded in a PowerPoint presentation).
To view all parent documents of the current document, in the document viewer, click the RELATED DOCUMENTS dropdown and then click the Family dropdown. Hover over the documents to view the document details. The following information is displayed for each parent: filename, custodian, author, creation and modification dates, the parent emails, and any tags. Click the document to navigate to it, or use the SHIFT + up/down keyboard shortcut to navigate to the next or previous document.
NOTE: By default, when you tag a parent document, all of the parent's children (attachments) are tagged. The inverse is not true; when you tag an attachment, the parent is not tagged.