Implementing push notifications with Azure Notification Hubs on iOS is very simple to set up from Azure's perspective. The most complicated part is working through Apple's process of creating certificates and provisioning profiles in order to configure your iOS application. Before continuing, make sure you have a valid iOS Developer Program account, as you will not be able to send push notifications without it. If you are unfamiliar with the concept of push notifications, take a look at Apple's documentation at http://tinyurl.com/XamarinAPNS.
To send push notifications, you need to set up the following: