I not able to pair Xiaomi ear pieces

Have you followed the directions from Xiaomi on exactly to pair your headphones? Usually, when earbuds are in pairing mode, you see blinking lights, then open Bluetooth settings on your iPhone and when you see them appear below, tap them to pair them at which point you will see Connected.

Do you have them in pairing mode when trying to connect?

Then you should reach out Xiaomi for help with their product. It's not an Apple product.