In your developer account, enable the push notification service for the App ID assigned to your project. In this tutorial, we'll show you how to add push notifications to your iOS app for free using OneSignal.Notification Service Extension is useful for storing notification data in the background mode or when inactive. When you create your AppID in the iOS Provisioning Portal you must configure it for Apple Push Notification service (read the "how to" tab). Generate notifications and push them to user devices. In this article, we will explore the step-by-step integration of push notifications into our iOS apps and discuss the critical aspects of implementation. First, you have to change the bundle identifier. In Xcode, highlight WenderCast in the Project navigator, then select the WenderCast target. Set up an Apple Push Notification service (APNs) certificate. You can send notification messages to drive user re-engagement and retention.