If you have files or folders you access frequently, you’d want them to be easy to reach. That is why you can now bookmark your most important files and folders. They will appear in a separate bookmark folder in your document library, so you can reach them quickly without having to constantly look for them.
If you select an item like a folder or file, you can bookmark that file from the actionbar. The bookmarks can be found back under the Bookmark on the left. Bookmarks can be removed or renamed.
You don't have to worry if you move your file to a different location. The bookmark will remain intact.