How to check battery information
You can get an idea of your battery's health by checking its maximum capacity, cycle count, date of manufacture and date of first use
To find battery information:
Press the Control Center button
Tap Settings icon
Tap Battery
Tap Battery Information
How to toggle battery charging between 80% and 100%
Limiting battery change to 80% can help maintain battery health.
To toggle charging between 80% and 100%:
Press the Control Center button
Tap Settings icon
Tap Battery
Tap Battery Information
Tap the Stop charging at 80% toggle switch