Unwanted showings of PREVIEW of variations of Word documents - can't delete those previews

I created a Word document and then edited it several times to get it "right."  I want to delete all the unneeded versions and save just the FINAL version. However, when I try to delete those WORD docs, a preview panel appear at the right of my PD screen with a message -- "unable to delete the document because the file is open."

How do I shut off the PREVIEW function so the document isn't "open" - so I can delete unwanted versions?

Mike Mottler
mottlermike10@gmail.com