Google Drive added comments to Microsoft Office files
Google Drive makes it easier for teams and agencies to use a mix of G Suite and Microsoft Office while working with their colleagues and customers. From now Google Drive users can easily comment on Office files, PDFs and images in the Drive preview pane without having to use (and potentially pay for) tools like Microsoft Office or Acrobat Reader — or having to convert them to Google Docs, Sheets or Slides files. That’s not quite the real-time commenting feature you get from G Suite or Office 365, but it’s still better than having to constantly convert documents back and forth between Office and G Suite.
Google Drive alternatives are: OneDrive, DropBox, Box, iCloud, SugarSync, Evernote, Amazon Cloud Drive, Google Docs