ID3 version provides minimal information. The first 128 bytes of the file contain title, artist, album, year, genre and comment information. The header begins with the string "TAG".
ID3 Version 2+ is much more complicated than v1, and may contain a wide variety of information, including attached pictures, lyrics, encoding software, file owner and payment data. In practice, the most commonly used fields however tend only to list such information as album, artist and track details.
The header may be placed anywhere in the file, being preceded by the string "ID3".