Push notifications are messages sent directly to a user's device from an app or website. They appear on the screen even when the app is not open, providing timely updates, reminders, or alerts. Users can receive these notifications on smartphones, tablets, or computers, making them a convenient way to stay informed. These notifications can be personalized based on user preferences and behaviors, enhancing engagement. For example, a news app might send breaking news alerts, while a shopping app could notify users about sales or new products. Users can usually manage their notification settings to control what they receive.