Any browser should be able to view Office 2016 documents, however to edit an Office 2016 file, Internet Explorer 11 must be the browser in use.
- Open Internet Explorer 11 and navigate to the appropriate SharePoint library
- Click the file name link and select "Open in..".
- If an error appears, go back to the list view.
- Check the file name.
- Either click the "Edit Document" button or select "Open in.." from the drop down menu.
The Open in Word option in Sharepoint
Edit in Microsoft Word context menu