If you are a subscriber of Adobe Export PDF service, then you can only export a pdf file to word document. From the above information, if I understand correctly you have a scanned document and would like to convert it to a work doc using Adobe Export PDF?
The file that you would like to convert to the word should be a pdf file to start with.
You may refer to- Using Adobe Export PDF for how you can convert a pdf doc to word.
If you are trying to create a word file from any other format, then that's not possible with the Export PDF subscription.
Hope this helps.