Explanation

MS Paint is a basic image editing software included with the Microsoft Windows operating system, does not support the ".doc" file extension. The ".doc" file extension is used for Microsoft Word documents, which are text files that contain formatted text, images, and other elements. MS Paint is a raster graphics editor, that is designed to create, edit, and view images, not text documents.

MS Paint only supports a limited number of image file formats, such as BMP, GIF, JPEG, PNG, and TIFF. If you want to open a document created in Microsoft Word in MS Paint, you would need to first convert the file to an image file format that MS Paint supports (e.g. PNG, JPG etc.)