This may include adding new items, magic, quests, dungeons, houses, and followers enhancing models, textures, gameplay mechanics, immersion, and the user interface or fixing bugs and inserting cheats. Mods are generally categorized by the changes they make to the game.
For policies and guidelines on documenting mods, see UESPWiki:Mod. The modspaces (this namespace and those associated with it) are places to document the contents of Elder Scrolls mods, in addition to all other things modding, hacking, and datamining, including using mods, making mods, file formats, and more. They may add new content, change existing features/mechanics, fix bugs, add cheats, and so much more.
Mods, short for modifications or modules, are user-made add-ons for video games.