When hosting music locally, you can decide between qualities that you want. If you don't care about quality or want to keep the storage size low (~2mb for a 3 minute song), look at MP3's.
If you do care about quality and have storage to spare (~30mb for a 3 minute song), look into FLAC's.
If you don't know that music has quality or can't notice the difference if you have, just choose MP3's. You can always rework your library later if you want to change (like I did)
If you specifically want to find a music player, try looking at my suggestions in the players section
If you specifically are looking for how to edit a song's metadata, follow the editing metadata section