I want to know my battery health

perez ~ Apple's iPhone User Guide says: "If your iPhone isn’t working as expected, you can try restarting it by turning it off, then turning it back on.":

Turn iPhone on or off - Apple Support

õ¿õ¬

Battery Performance Tips:

• iPhone Battery and Performance.
• Maximizing Battery Life.
• About battery usage.
• Check the iPhone battery health and usage.
• Optimized Battery Charging.
• Use Low Power Mode.

Need more help?

• Call Apple Support at 1-800-APLCARE.
• International Support.
• Contact Apple Support.
• Chat using Messages.