Direct Edit enables to edit any of your document's content even if they are not synchronized. To be able to use correctly Direct Edit you need the Drive addon on your server and you must turn on Drive on your computer. This saves you the fastidious steps of opening your document, modify it and reimport it on your platform.
The icon looks like 
on Web-UI and 
on JSF-UI.
To edit a document locally from the web interface:
On the document in the Nuxeo Platform, click on the Direct Edit icon on the document View on Web UI and on the Summary tab on JSF UI. The document opens in its native application (OpenOffice.org for an .odt file for instance).
If you plan to work on the document for some time, you can easily lock it from the Metadata edit popup (see the section Metadata Edit). Note that depending on your OS and the file format, the document can be automatically locked. This is still a beta feature of Direct Edit, known to currently work on macOS and Windows.Edit the document and save the modifications. Modifications are saved in the Nuxeo Platform directly.
- Close the document.