SimpleMDM, by default, will not push iPhone and iPod-only apps to iPad. In these situations, there is often an iPad-only version of the app as well. By not automatically installing iPhone/iPod apps to iPads, an administrator can assign apps of different "platform" to a group of devices of different platform and ensure that devices receive the appropriate version of the app.
In some cases, this is not desired. For instance, some apps are made for iPhone and iPod and do not have a separate iPad app. SimpleMDM allows you to force an iPhone/iPod app to install to iPads anyway.
To modify an app, go to the app details screen for the app and select the "Force iPad compatibility" option.