Wikipedia
DirectDraw is a deprecated API that used to be a part of Microsoft's DirectX API. DirectDraw is used to accelerate rendering of graphics in applications. DirectDraw also allows applications to run fullscreen or embedded in a window such as most other MS Windows applications. DirectDraw uses hardware acceleration if it is available on the client's computer. DirectDraw allows direct access to video memory, hardware overlays, hardware blitters, and page flipping. Its video memory manager can manipulate video memory with ease, taking full advantage of the blitting and color decompression capabilities of different types of display adapters.
DirectDraw is a 2D API. That is, it contains commands for 2D rendering and does not support 3D hardware acceleration. A programmer could use DirectDraw to draw 3D graphics, but the rendering would be slow compared to an API such as Direct3D which does support 3D hardware acceleration.
DirectDraw was introduced for Windows Mobile in Windows Mobile 5.0, replacing the graphics component of GAPI, which was then deprecated.
DirectDraw has been deprecated since version 7. As of DirectX version 8.0, DirectDraw was merged into a new package called DirectX Graphics, which extended Direct3D with a few DirectDraw API additions. DirectDraw can still be used by programmers, but they must use older DirectX interfaces (DirectX 7 and below). As of the release of the June 2010 DirectX SDK package, the DirectDraw header file and library are no longer included.