Kid3 Audio Tagger is a free and open-source software that allows users to easily edit and tag audio files in different formats such as MP3, Ogg/Vorbis, FLAC, MPC, and more. With Kid3, users can add or edit tags like title, artist, album, genre, and year, as well as add cover art and lyrics to their audio files. The software also supports batch processing and can rename files based on their tags. Additionally, Kid3 allows users to export their tags to different formats like CSV, HTML, and playlists.