Firstly, Rapise uses the open-source Appium API to connect to devices to automate them, this is similar to how you can access a web browser using the Selenium WebDriver API.
Unfortunately, it is not possible to automate iOS app store apps using Appium (due to the Distribution Certificate used on all app store apps) since Appium requires that the code is signed with a development certificate. This means you cannot access the app via Appium as-is.
So, if you only have the App on the app store, it is not possible for Rapise to automate it.
To do automation testing on a iOS app it should be signed with development certificate not a distribution certificate.
So to automate such an application, you need to have the source code for the application in question, and you need to be able to build it an run it from within Xcode. In this case it will be possible to run & test it on the Simulator with Rapise (and Appium).