Because you seem to be confused, I'll try and spell it out for you. A FLAC file is nothing more than music that hasn't been compressed. If you have a cd and you rip it to your computer, depending on what programme you use to rip it, you can choose FLAC, WMA, MP3 or maybe others. When you rip it in FLAC, you generally aren't compressing the music at all so it is just like it is when you play the cd itself. If you use MP3, you can compress it to save space to fit more music on a drive but you run the chance that it might not sound quite as good as FLAC. MP3s that are ripped at a very high bit rate, 320 or close to that, will likely have no noticeable sound difference from FLAC regardless of what anyone will try and tell you.
So basically, a FLAC file is just a type of uncompressed file as is WMA and some Apple file (I don't do Apple so I don't know which one it is).