Unfortunately, no. Word Online preserves columns that are already in your document, but it doesn’t yet provide a way to create them.
If you have the Word desktop application, use the Open in Word command to open the document and create newsletter-style columns. When you’re done and you save the document, it will continue to be stored where you opened it in Word Online. When you reopen it, the columns will be there.
Word Online works seamlessly with Word and other Office desktop programs, and we update it based on input like yours. For the latest feature announcements, visit the Office Online blog.