All wireless providers deliver government-issued Wireless Emergency Alerts (WEA) to iPhone owners on their networks. The capability to receive these alerts was added with a Carrier Settings Update in 2013. There are three types of alerts, two of which iPhone owners can turn off.
Notification badges are great at doing their job - letting you know that there is something you need to look at in the notifying app. The problem is they can easily become overwhelming if you have tons of apps constantly demanding attention for every minor event. While you likely want to know when new emails are sitting in your work inbox, you may not want to know every time your troops are ready to battle, or every time somebody has posted in a Telegram room with 10K subscribers.
You can change your apps' notifications in Settings -> Notifications on a per app basis. Tap on Notification Grouping at the bottom of any app that has notifications turned on and choose Automatic, By App or None.
iOS 12 introduces the ability to "tune" your notifications from the Notifications Center. Swiping left on an notification or a group of notifications will now bring up 3 options: Manage, View, Clear All. Tapping "Manage" gives you the option to deliver notifications quietly. Quiet notifications will still appear in the notification center but will not play a sound, appear on your Lock screen, or present a banner or badge icon.