To start editing a document, it is as easy as clicking on
the file name in the file listing. The
Collabora Online editor will start and you can begin to edit your document
inside your browser.
When
you make changes to the document, the “disk save” button will change from 
to 
indicating
there are changes to be saved. There is
automatic saving feature when editing.
You can click on it to manually save your changes if you wish.
On
the right-hand side of the menu interface, there are the sidebar and close
document button 
. Use
the close document button to exit editing and return to Nextcloud Files App.