How can I make Dropbox files available offline on Android?
As the rest of the paragraph says, you can also mark it as a favorite by opening it in Dropbox (on Android) and starring it, or by swiping it left to right (on my phone, giving it a long press brings up the option).
The answer can be found on Dropbox's help site https://www.dropbox.com/help/82/en :
The mobile app shows you the list of your files, but it only downloads them as needed, such as when you tap on a file to view it. To ensure that a file is always on your device, mark it as a Favorite by either swiping left to right or viewing it in the app and tapping the star icon
Thanks. You mentioned "..it only downloads them as needed, such as when you tap on a file to view it... " Please specify how to locate folder of downloaded files from list of synced file list in dropbox for android?