Your songs on iTunes are sound files. If you downloaded them from the iTunes store, they are .m4a files. If you downloaded them from elsewhere, they may be in a different format, but they are still sound files. To locate the files on your hard drive, simply right click on a song on iTunes and click "Show in Windows Explorer" (at least on Windows).
Music files downloaded from the iTunes store come in the format "Purchased AAC", and video files downloaded from the iTunes store come in the MP4 format
The program used to store files on windows is called: Windows Explorer.
Whichever drive u want to store it it will ask for it
to store files
On the hard drive with uncompressed files.
It is used to store offline files and folders
The Google Play Store can't be downloaded on a Window's phone at this time.
Registry
Practically anything, for example: photos, downloaded games, files, etc.
TMP or temp files are temporary Windows files used to store temporary data or be used as a backup for files that are being used.
The files which store the copy of your original data are called backup files. In windows backup files are created by NTbackup utility and windows backup and restore utilities. These backup files have .bkf file extension.