I recently had to do the same thing, in my case I was setting up my books for amazon's Kindle reader.
In their set up wizard Amazon advise they prefer files in an HMTL format and you can do this fairly easily in MS Word itself.
Bring your Word document onto the screen go to edit and select all and copy to a new document.
Select the Save As Button and then select 'Other Formats.'
From the list chose to save your file as a Web Page and this will give your file an HTML tag.
This should download into into any EBook reader.