Windows 7 Audacity 2.2.2: Exporting

I edited a 24 bit audio file that was created on a ZOOM h2 recorder.
When I Exported the edited file it asked me to chose between 16 bit (PCM) or 32 bit (PCM).
What do those choices mean?
Also, by selected one or the other, does that change the exported file’s bit as I would like to keep it at the original 24 bit?

yes - the 24-bit WAV export can be a bit hard to find …

  1. Use File > Export Audio
  2. choose Other uncompressed files
  3. in the Format options for Header choose: WAV
  4. in the Format options for Encoding choose: Signed 24-bit PCM