Quiet Mode could be switched on manually or scheduled as per your preference. This allows the user to specify a daily timeframe for Quiet Mode that allows Facebook to automatically turn it on without having to open the app. How to turn Quiet Mode to Facebook:
Open the iOS (available) or Android Facebook appGo to the profilePress the three rows in the bottom right corner, and then look for the Privacy and Press Settings
Press on your time on Facebook
Turn on Quiet Mode
As of now, this feature is only available on their iOS app, which is available for iPhone and iPad.