NOTE: With this new update, the 'Open in quick view' will be automatically on.
Turning on document preview
Go to Documents.
In the toolbar above your file list, click the panel icon next to the list/grid view toggle (top right).
Check Open in quick view.
What happens when it's on
With Open in quick view turned on, clicking a document opens a preview panel on the right side of the screen. You can see the document's contents without leaving the Documents list.
From the preview panel, you can also:
Request signatures
Download
Move
Open the document in the full editor
Copy link or Share
Review File info
Make a copy
Rename
Star as a favorite
Delete the document
To open the document fully, double-click it (or use Open in the preview panel).
What happens when it's off
With Open in quick view turned off, clicking a document opens it straight away in the full Lumin editor; there's no preview step in between.