Let's face it, the IOS version of Google Drive has not been the Holy Grail of Google Greatness. In addition, it has not been nearly as user-friendly as it is on the Android system. It has been lacking for some time, but there have been some great improvements over the past year (we finally got collaboration on Documents and Spreadsheets). Overall, function has been quite limited but is getting better. Thank goodness Google keeps updating the IOS Drive app. In the latest update, it now supports commenting. Now, you can comment on documents on your iPad just like in your browser on your computer. All the steps are the same (highlight text, create comments). We are getting closer to the web based version. My fingers are crossed that soon the mobile version is as great as the desktop web version.