Use these steps to view data usage on the Apple iOS 11. Check the software version using Software versions & updates: Apple iPhone & iPad on iOS 11.
- From the Home screen, tap Settings > Cellular.
- Scroll down to view apps and how much data each one has used.
- The default view is This Billing Period. Tap Last Billing Period to view the previous month's usage.
- If you want to stop an app from using data over cellular, tap the switch to turn it off.