You say word documents, by this do you mean .doc or .docx file formats?
If so there may be some conversion involved (perhaps as easy and resaving (Save As) as a .rtf in MS Word). The markup for formatting in native word documents (.doc/.docx) isn't the same as .rtf. If already in .rtf file format then in theory yes it should be as simple as mounting (plugging in) the Kobo and copying/moving the files onto the device. I personally haven't tried .rtf files so I can give you specific feedback. Perhaps others who have can chime in.