How to turn off data on an iPhone

You can turn off data on an iPhone all at once, for specific apps, or by turning on Airplane Mode through the Control Center.
CNET

Before Upgrading to an iPhone 17, Turn Off This One Setting on Your Old Device

1. Tap Settings on your iPhone. 2. Tap Face ID & Passcode. You might have to enter your Passcode here to continue. 3. Tap Stolen Device Protection. 4. In the new menu, toggle on Stolen Device ...

How to turn off data roaming on your iPhone for international travel, or completely turn off cellular data

It’s a good idea to turn off data roaming on your iPhone if you want to avoid using data while traveling internationally.
MacRumors

iOS 26: Enable or Disable Adaptive Power Mode

In iOS 26, Apple offers a new Adaptive Power Mode that works alongside the existing Low Power Mode to intelligently extend your iPhone's battery life. Unlike Low Power Mode's heavy restrictions, this ...