In order to develop applications with Telerik UI for Xamarin.Forms you need to have the following development tools installed:
- Windows 8.1 or higher. You would need Windows 10 in order to develop for UWP.
- Visual Studio 2013 and Xamarin installer (downloaded separately) or Visual Studio 2015 or Visual Studio 2017.
- For building iOS apps - configured iOS build host
For more information on how to setup your development environment check this MSDN article
You will be able to develop Android and iOS apps. The iOS apps will require iOS 7 and higher. Windows apps are not supported on OS X.