The TrueType font system marked the most important visual innovation in Windows 3.1. True Type was actually developed by Apple Computer, which, if you can believe it, licensed the technology to Microsoft for free. Why? Apple didn't want Adobe to monopolize digital type.
Rather than using blocky pixels in a bitmap, TrueType described fonts as curves and lines, which allowed fonts to scale smoothly to any size. This capability produced amazing printed documents, a big reason why Windows 3.1 flourished as a desktop publishing platform. Win 3.1 included 15 fonts with now-familiar names such as Arial, Courier, System, and Times New Roman.