Dark mode allows you to change the color theme of WhatsApp from white to black and can be enabled or disabled in your device settings or Control Center. This feature is available on iOS 13 and above.
Enable dark mode from device settings
Go to iPhone Settings > Display & Brightness.
Select from the following options under APPEARANCE:
Dark: Turn dark mode on.
Light: Turn dark mode off.
Automatic: Enable dark mode to turn on automatically at a specific time. Select Sunset to Sunrise or set a Custom Schedule.
Enable dark mode from Control Center
Go to iPhone Settings > Control Center > Customize Controls.
Add Dark Mode under INCLUDE to have it appear in Control Center.
Open Control Center:
On iPhone X and newer, swipe down from the top right of the screen.
On iPhone 8 and older, swipe up from the bottom of the screen.
Tap the dark mode icon to turn dark mode on or off.