There's currently no way to delete notifications; however, if you'd like to turn off the notifications on your phone, please try the following steps:
1. Tap the "Profile" icon in the bottom right of your screen
2. Tap "Settings & Preferences" under the "Info" section towards the bottom of the page, followed by "Communication Preferences"
3. Toggle whichever alerts you would not like to receive to "off"
4. You can also select "Unsubscribe All" at the very bottom to unsubscribe from all notifications.
All notifications should stop after you turn this off.