Blue light might harm your ability to sleep. You can filter out the blue light from your display with the following tools:
For iPhone 5s and iPad Air 2 or later:
1. Swipe up from the bottom bezel onto the screen to bring up Control Center.
2. Tap the Night Shift button to enable/disable.
Advanced Night Shift settings can be found in Settings (accessible from the Home screen) under Display & Brightness.
For Android 7.1 Pixel,Pixel XL and newer devices:
1. Swipe down twice the notification shade to access the Quick Settings menu.
2. Tap the moon icon (Night Light) to enable/disable.
Advanced Night Light settings can be found in Settings (swipe down from the notification shade on home screen), then Display, and lastly the Night Light option.
Night Mode Enabler app
For Android with Nougat operation system and Nexus devices:
First, make sure the System UI Tuner is enabled:
1. Pull down the notification shade twice.
2. Long press the cog icon and release after a few seconds. A wrench icon will then show up beside the cog, indicated the UI Tuner has been enabled.
Next, install the Night Mode Enabler app:
1. Install the app.
2. Open the app. It should open System UI Tuner menu with Night Mode options. You can set up your preferences here.
For Non-Nougat devices: