For the core gameplay, you can download from official app stores like Google Play or the Apple App Store.
If you want a physical or grid-based layout for your dungeon design, PaperDungeonMaker allows you to generate and download serialized CSV files of your dungeon grids, which can be printed or used for further development.
Many players use the Dungeon Maker Wiki to reference difficulty unlocks and character builds when "preparing a paper" strategy guide for their own runs. PaperDungeonMaker by 0x72
This is a dedicated app for Dungeon World players to manage character classes, stats, and session notes digitally.
Since you asked to "prepare a paper," you are likely looking for a companion tool to design or track your progress. Here are the best options: