Why isn't there "Word document" option in the "Export" of my OneNote 2016 "File" tab?
OneNote 2016's "Exported as a Word document" feature that requires you to have the same version of Word 2016 installed, The Word document options appear in Export and Send after installed Word 2016.
Cannot Install Word 2016:
There is a special place, if your OneNote is downloaded and installed from onenote.com. This is OneNote 2016 free version, it is no longer possible to install Word 2016 with it.
You need to uninstall this free version, and install Office 2016 or Office 365 to install Word 2016.