Turning a WAV recording into a shareable MP3
What each format is
WAV is the uncompressed format used by recording software, and it keeps every sample. MP3 is a lossy format that removes detail the ear barely notices. That trade is why an MP3 can be a tenth of the size.
The size difference is the reason
Three minutes of CD-quality stereo WAV is about 32 MB. As MP3 it is typically 3 to 7 MB depending on bitrate. At 128 kbps one minute is about 1 MB, at 320 kbps about 2.4 MB. That gap decides whether a file can be emailed, uploaded or played from a small phone.
Good jobs for this conversion
Voice memos recorded in WAV, interviews, rough mixes sent to a band-mate, podcast drafts and sound effects for a website all do well as MP3. Dense, wide-range music is where lossy compression is easiest to hear, so be more careful there.
What gets lost and what does not
MP3 removes very high frequencies and detail masked by louder notes. It does not change pitch, speed or length. A very small gap can appear at the start or end of an MP3, which matters for gapless albums but not for most recordings.
Keep the WAV
Lossy conversion is a one-way trip. Once you have the MP3 you cannot recover the WAV, so store the WAV somewhere safe and use the MP3 as the copy you share.
Recording your own voice? Record and edit in WAV, and make the MP3 as the very last step.