HOW TO USE NIGHT SHIFT ON YOUR IPHONE
Released in iOS 9.3, the Night Shift feature in iOS allows you to filter out blue light and adjust the warmth of the colors in your display. To turn it on go to:
Settings > Display & Brightness > Night Shift
There is an option to select the hours that best suit you. You can also choose Sunset to Sunrise to have iOS pick hours automatically based on your location.
HOW TO USE NIGHT LIGHT ON YOUR PIXEL PHONE
On Google’s Pixel phones and some other stock Android devices running Android 8.0 Oreo and later you can find a blue light filter option here:
Settings > Display > Night Light
Tap on Schedule to specify your own hours and change the level of filtering with the Intensity slider.
HOW TO USE THE BLUE LIGHT FILTER ON SAMSUNG GALAXY
Most Samsung Galaxy phones have a blue light filter option now. The fastest way to turn it on is to pull down your notification shade and swipe down again to access your quick settings. One of them is called Blue light filter and you can tap to toggle it on and off. You can also do it through Settings:
Settings > Display > Blue light filter
You can adjust the opacity with a slider and you can also select Turn on as scheduled and then pick Sunset to sunrise or Custom schedule if you want to specify your own preferred hours.
HOW TO FILTER BLUE LIGHT ON OTHER ANDROID PHONES
You’ll generally find a quick setting option in your notification shade and scheduling options in Settings > Display.
LG calls it Comfort View, HTC and OnePlus call it Night Mode, Huawei calls it Eye Care, Motorola calls it Night Display, and Xiaomi calls it Reading mode.
If your Android phone comes without a blue light filter, you can always try a third-party app like Twilight on the Play Store.