You can connect to the mobile-friendly versions of your apps by logging into your Edmodo account on your iPad. When you click the Apps tab on the left-hand navigation column, you will see the mobile-friendly apps you have access to on the resulting Apps page. To launch an app, simply tap on its icon.
Note: The "Apps" tab will only appear if you have apps that have been installed to your group(s). The mobile-friendly apps are available on Android too if you access the full-web version of Edmodo via a browser.