Modding
Modding is the process of modifying Minecraft’s default experience to add or change features, game mechanics, and Gameplay.
Mods and other Project types have greatly extended the already infinite possibilities of Minecraft. Today, modding has become much easier than in the past, but it remains challening because Minecraft is not designed to allow modifications apart from Resource packs and Datapacks.
Datapacks can extend the Vanilla experience, but are not suitable to add new features, and without Loaders, modding would not be possible.