Steps
- Open Settings > Blacklist.
- Choose User apps or System apps, or use the filter to find the app.
- Tick the app. It is now blacklisted.
- Untick it to start tracking it again.
What happens
Notifications from a blacklisted app are not logged. They may still ring alarms if Process Blacklisted is on (see "How to let blacklisted apps still trigger alarms").