So there are two places to configure notifications in iOS. The first is within the Blink app, and the second is in the phone’s settings menu.
In the blink app, tap the hamburger menu (the three stacked horizontal lines in the upper left corner of the app’s main screen), then manage account, then you should see the notifications menu.
In iOS settings, scroll to the blink app, tap on it and then tap on notifications.
Essentially, the app’s notifications page allows you to configure which types of events will result in the app sending a notification. The iOS settings screen configures how the device displays the notifications.