Cool thanks Rōnin!
I use Logic Pro and can export mp3 files with custom metadata but it doesn't seem to have this option when it comes to exporting wav files, unless I'm blind and I'm not seeing how to do it haha
Ah, I hadn't mentioned that wav files don't actually have artist/song information in their metadata header (i.e. don't support ID3 tags), so this is something you can't do with wav files. I know mp3 and flac files do have it, and some others (but I don't know which ones)
EDIT: I might be wrong on the WAV thing actually. I did a quick search on it and it seems there's even metadata editing software:
http://taglib.github.io/