Click on the button the arrow is pointing to below- affectionately termed the “Kitchen Sink”- in order to get additional options for your editing toolbar.
Go from this:
After following the step above you will see an icon with the MS Word icon in your visual text editor (which the arrow is pointing to). Click on this and copy the Word Document text into this window and save it. This strips out all the MS Word code and “cleans” the text for publishing on WordPress. There may be some minor formatting you have to update afterwards, but most of the formatting from MS Word should remain intact.