@pratik Yes, it will the sync the previews, which you can edit in LR Mobile or on the web and the edits will sync back to your original file.
It's a "manual" mirror. I drag a "local" folder onto the collections area (in a folder or subfolder if you wish so) and check the sync mark.
If you have sync enabled, and if the collection is a static collection (smart collections can't be synced), there should be a faint square box in front of the collection name. Clicking in that box should initiate syncing, (the two-way arrow icon will appear). Quick screen capture here: vimeo.com/503216282