How do I check my battery

Settings > Battery

The battery charge appears on the top right edge of your screen.

Where is the Battery Health of your iPhone? Open Settings ➔ Battery ➔ Battery Health and check what percentage you see for Maximum Capacity. Also note what is written under Peak Performance. If your battery's Maximum Capacity shows a value of 80% or less then it has gone through its lifecycle and therefore should be replaced, according to Apple.

Axel F.