Lossless formats like WAV preserve the full audio fidelity of your recordings, unlike MP3, which sacrifices detail through compression.
Because MP3 is a “lossy” format, it discards data to reduce file size—making it less precise in sound—despite its widespread use.
eMastered supports WAV, FLAC, and MP3 uploads. If you choose MP3, make sure you're satisfied with its sound quality before distributing.
Your choice is ultimately yours, but selecting a lossless format like WAV or FLAC ensures the best audio integrity and satisfies listeners who value high-quality music.