A notification is a message or alert that informs a user about an event or update. It can appear on various devices, such as smartphones, tablets, and computers, and is often used to convey important information, reminders, or changes in status. Notifications can come from applications, social media platforms, or system updates, helping users stay informed and engaged. Notifications can be categorized into two main types: push notifications and in-app notifications. Push notifications are messages sent directly to a user's device, even when the app is not open, while in-app notifications appear within the application itself. Both types aim to enhance user experience by providing timely information.