Tập tin dữ liệu trò chơi được dùng bởi Doom và Doom II, cũng như các trò chơi xạ thủ đầu tiên sử dụng động cơ Định Mệnh gốc;chứa dữ liệu như ma quỷ (đồ họa), thông tin cấp độ và các mục;dùng để lưu trữ nội dung game và sửa đổi trò chơi.

The WAD format has been classified into two categories: 1) IWAD ("Internal WAD") and 2) PWAD ("Patch WAD"). The IWAD file type is used for loading core game content, and PWAD files are used for adding optional data to the game. Because of the popularity of Doom and the customizability of WAD files, the WAD format became one of the more widely known and widely used game data file formats. Community gamers developed thousands of mods using WAD files for Doom and other games. However, since Doom and Doom II were released in the 1990s, the format is not as commonly used as it once was. The original WAD format, referred to as WAD1, evolved into subsequent formats, which include WAD2 and WAD3. These versions were reduced in scope to include only game textures and were used for Quake and Half-Life. Quake WAD texture files can be edited with programs such as Wally.