To turn Low Power Mode on or off, tap Settings > Battery.
Your iPhone will last longer before you need to charge, but some features might take longer to update or to complete. Some tasks might not work until you turn off Low Power Mode, or until you charge your iPhone to 80% or higher. After you charge your iPhone to 80% or higher, Low Power Mode automatically turns off.
Low Power Mode reduces or turns off these features:
- Email fetch
- Hey Siri
- Background app refresh
- Automatic downloads
- Some visual effects
When Low Power Mode is on, the battery in the status bar will be yellow. You'll see 
and the battery percentage.
Low Power Mode is available only on iPhone.