This article explains how to activate Night Shift on the iPhone and how to automatically schedule this feature at certain times of the day. Night Shift is a blue light filter that helps avoid disrupting the circadian rhythm at night, improving sleep quality.
Steps
Part 1 of 2: Manually Activating Night Shift

Step 1. Open the iPhone Control Center menu by sliding your finger up
A series of boxes and icons should appear on the screen.

Step 2. Press and hold the vertical bar called "Brightness" (represented by the sun symbol)
Holding it down firmly for one second will open the menu associated with the brightness settings.
If you don't hold the button down, the menu won't open

Step 3. Tap Night Shift, a circular button at the bottom of the screen
If it turns orange, the function will remain active until the stroke of midnight.
If it is already orange, then it is active. Tapping the button again will disable it
Part 2 of 2: Programming Night Shift

Step 1. Open the iPhone settings
tapping the icon, which looks like a gray box containing a gear.

Step 2. Scroll down and tap Screen & Brightness
This option is found under "General"
at the top of the settings page.

Step 3. Tap Night Shift
It is located at the top of the page.

Step 4. Tap the white button
"Program".
It is located at the top of the page. Touching it will turn green

Step 5. Tap the From-To section, which appears under the "Schedule" button once it's activated
A page with programming options will open.

Step 6. Select a schedule option
By tapping "From Dusk Till Dawn", the iPhone will activate Night Shift at dusk and deactivate it at dawn. If you tap "Ad hoc", the time can be configured manually.
To set a custom time, tap "Turn on at" and select the time. Then, tap "Turn off at" and select the time

Step 7. Tap"
Night Shift at the top left to save and apply changes.
The function should turn on and off automatically depending on the selected program.