Yes, you generally need to have a mobile app installed on your phone in order to receive push notifications from that app. Push notifications are typically sent by the app’s server to the user’s device, and the app then displays the notification to the user.
When you install a mobile app on your phone, you are typically given the option to allow the app to send you push notifications. If you opt in to receive push notifications from the app, the app will be able to send you notifications even when the app is not currently open or in use.
It’s worth noting that some operating systems, such as iOS and Android, allow users to manage their push notification settings on a per-app basis. This means that you can choose to turn off push notifications for a specific app, even if you have the app installed on your phone.