Easily take control of your notifications.
Just as Screen Time gives you more insight into how you use your devices, notification management in iOS 12 gives you new ways to reduce interruptions throughout your day. You can now manage your notifications in real time from the Lock screen, sending notifications from a specific app to Notification Center or turning them off altogether. Siri also makes intelligent suggestions about your alerts based on how you interact with them. And message threads and notification topics are grouped together, so it’s easier to see what’s important at a glance
Do Not Disturb
iOS 12 gives you more ways to manage your notifications than ever, but there are times when you don’t want to be disrupted by any alerts, messages, or calls at all. So now you can set Do Not Disturb just for a meeting or while you’re at a location, and it will automatically turn off as soon as your event ends or you leave that place.
I have not seen the Keynote. I took a quick look through the iOS 12 feature list and I think the updates to "Do Not Disturb" and "Notifications" may be my favourite part of the OS update.