FLAC is the audiophile's handshake: CD-perfect sound at roughly half the shelf space. It was born in 2001, Josh Coalson; now kept by the open Xiph.Org Foundation, and its real weak spot is fitting in pockets: lossless is still large: and charming Apple's own apps.
WAV is audio with nothing taken away: every sample intact, every megabyte accounted for. Raw PCM samples in a RIFF wrapper. No compression of any kind. That makes it the right destination when what you need is recording, editing and mastering, where every last bit matters.