my iphone battery usege not showing ?.

Greetings nadishan,

If you are seeing unexpected behavior from your iPhone, begin by restarting it, using the steps found here:

Restart your iPhone - Apple Support

"How to restart your iPhone 6, 7, 8, or SE (2nd or 3rd generation)

1. Press and hold the side button until the power-off slider appears.
2. 
3. 
   
4. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
5. To turn your device back on, press and hold the side button until you see the Apple logo."

Take care.

The phone must be powered on for at least 24 hours before usage information will show.