Playlist formats TXT and HTML are creating by mask defined in Index setup window.
Playlist created with mask:
[%Track%] - %Artist% - %Title% - (%Time%)

Playlist formats M3I and DBF are saved with all major mp3 information.

Playlist M3U is standard text file which contains full or relative paths to mp3 files. This file is usualy associated to your default mp3 player.

Playlist Examples:

M3U example (u2.m3u)
HTML example (u2.html)
TXT example (u2.txt)

NOTE: You can save your playlist with all inforations only if you have saved ID3 V1.x TAGs in your mp3 files.