App notifications are messages sent by applications on your device to inform you about updates, reminders, or new content. They can appear as banners, alerts, or badges on your screen, helping you stay engaged with the app. For example, social media apps like Facebook or Instagram use notifications to alert you about new messages, likes, or comments. Users can customize their notification settings to control which alerts they receive and how they appear. This feature allows for a more personalized experience, ensuring that important information is highlighted while minimizing distractions from less relevant updates.