Files is the official file manager developed by Microsoft for Windows Phone OS.
Launching the app, you are first presented with available memory locations, and information about used and free spaces. Lovely. My first time, O can see that I have 3.6GB used and 3.6GB free on my device. Info for SD Card was also displayed. From that same page, you can initiate a search for whatever file you are looking for. Otherwise, feel free to explore whatever storage space you want.
Diving in to explore, you are presented with a vertical, graphic list of folders first, followed by a list of files. Each folder is labelled with the number of folders and files inside it. Which again is very useful. Each file has its size listed in small font.
You can create new folders, select, delete, move, copy, share, sort rename, and again search. Tapping a file launches the default app for the file type and opens the file for viewing and editing.
Files for Windows Phone is a simple, neat and elegant file manager. It is however available for only Windows Phone 8.1 devices.