The default notepad included in Windows does not have feature to edit document in Rich Text formats. Document Editor is a tabbed text editor for Windows. It includes plain and rich text format support, multi tab interface so you can edit multiple documents in a session, compact application size, and multiple commands. There are some nice feature included in this tool like text to speech, adding links and also images.
It also has theme support and an in-build spell check.
Document Editor is an awesome text editor for Windows with tons of features and also easy to use.