Document data displays all the documents in the selected index. By default, document data shows 500 documents listed, with the most recent documents shown first. By default, document data displays the localized version of the specified time field in the selected index and document of field
_source. In document data you can add field columns, remove field columns, view document data, and sort documents.
It is very simple to add a field to document data. Fields can be added from the Fields list, which is at the left side of the Discover page and below the index name.
To add a field to document data: