Swipe down from the top-left corner of the screen to open Notification Center
Swipe left on a notification and tap Clear
Swipe left on a notification group and tap Clear
Tap X at the top of a notification group, then tap Clear All Notifications
Long-press a notification and tap Clear
Clear notifications from the Lock Screen by swiping left and tapping Clear
Turn off notifications for an app in Settings > Notifications
Use Focus mode to reduce or silence notifications
Turn on Scheduled Summary in Settings > Notifications to group notifications
Clear all notifications by opening Notification Center and tapping X if available