I want my app to start Service when the button is clicked and the Service should run in background to show a notification at a particular time of day. Notifications provide short, timely information about events in your app while it isn't in use.To receive messages, use a service that extends FirebaseMessagingService. Your service should override the onMessageReceived and onDeletedMessages callbacks. In today's post, we're diving into how to set up scheduled local notifications using AlarmManager. It's a cool trick to keep all your tasks in check. When the user taps a notification, your app must display UI that relates directly to that notification and lets the user take immediate action. In this video you will learn How to create a simple notification for our app. This article explains upcoming foreground service requirements and how to declare foreground service information in Play Console. To create a notification group, create a unique key for the group, and then just call setGroup for every notification, you want in the group.