iOS allows you to have a general idea of your battery's health. You do not get complete detail on your battery's health, such as the charging capacity.
The iPhone makes it easy to save data and battery power by turning on the Low Data and Low Power modes. Here's how to find and use them — and what happens when they're on. Make the most of your battery with Low Power Mode You might find yourself instinctively killing off background apps, turning on Airplane Mode, or disabling Wi-Fi and Bluetooth while your iPhone battery is critical to hopefully get a little more screen time. There are better options. Read more...