Wav is more or less “raw” audio. It is typically not compressed.

Ogg Vorbis is a lossy compressed format. It reduces the “quality” of the audio in exchange for a smaller file. More often than not, the change in quality is not perceptible to the human ear.

Other lossy compressed formats include MP3, AAC, and Ogg Opus. There’s plenty of neuance to compare between these lossy formats. But if you don’t already know about them, just assume Ogg Opus is best, Ogg Vorbis and AAC are the same, and MP3 is worse. AFAIK Spotify uses Ogg Vorbis, but they may have upgraded to Ogg Opus by now.

FLAC is a losslessly compressed format. It compresses the raw audio without changing the quality at all. All lossless formats are the same quality as Wav. The only differences between the lossless formats are the size of the file and the CPU cost to decompress the data.

Have more questions about codecs? Just ask! I’m not an expert but I do know a decent bit about this stuff.