Launch the Action Center by clicking on its corresponding icon in the taskbar. Notifications and alerts are sorted by type (Autoplay, Settings, Apps...). You simply have to click on a notification to view additional details.
Delete Notifications from the Action Center
Click on the x button displayed next to a notification to remove it from the Action Center:
Click on Clear all to dismiss all notifications from the Action Center.
Customize Windows 10's Notifications Settings
Click on Start > Settings and go to System > Notifications & actions > Notifications. Here, you'll find a couple of interesting options:
Show me tips about Windows: Display useful tips about Windows 10 in the Action Center (in the form of notification banners).
Show app notifications: Allow the apps installed on your computer to display notifications.
Show notifications on the lock screen and Show alarms, reminders and incoming VOIP calls on the lock screen: Allow Windows 10 and apps to display alerts and notifications on the lock screen.
Hide notifications while presenting: Stop Windows 10 from displaying notifications when your device is connected to an external screen or projector.
Choose Apps to Show Notifications in Windows 10
Windows 10 enables you can choose which apps should show notifications. Go to the Show notifications for these apps section and toggle the switches next to the desired apps to the On position:
Once done, click on any of the selected app to enable individual customization options such as Show notification banners and Play a sound when a notification arrives:
Mute Windows 10 Notifications with Quiet Hours
Quiet Hours is Windows 10's equivalent for the Do not Disturb mode available on other operating systems. It enables you to instantly mute notifications, alerts, and calls by right-clicking on the Action Center icon and selecting Turn on quiet hours: