How to save data usage on an iOS device?

• Enable Low Data Mode：Go to Cellular → select the corresponding line → turn on Low Data Mode.
• Control app cellular data usage (precise data limiting): On the Cellular page, turn off Cellular Data for apps you don't need to use on the go. They will then only connect via WiFi.
• Turn off Wi‑Fi Assist: This feature automatically switches to cellular data when your WiFi signal is weak. Path: Cellular → scroll to the bottom → turn off Wi‑Fi Assist.
• Disable Wi‑Fi Assist and iCloud Backup: Go to Settings → Cellular or Mobile Data → Scroll down and turn off Wi‑Fi Assist and iCloud Backup.

Wi‑Fi Assist and iCloud Backup may be enabled by default. If you don't want your device to switch to mobile data when your Wi‑Fi connection is poor, you can turn off Wi‑Fi Assist. Disabling iCloud Backup can also help minimize data usage.