I am not able to connects iPhone with other iPhone via Bluetooth . Any help ?

This is correct. This has never been a feature of iPhone/ipad/iphone.

Bluetooth is supported for handsfree telephone devices, stereo headset/speakers, some keyboards, some apps from the app store and internet tethering if provided by your carrier.

Other than this, it will not connect to computers or other phones.

here are the bluetooth profiles ios devices support iOS: Supported Bluetooth profiles - Apple Support

here are all bluetooth profiles https://en.wikipedia.org/wiki/List_of_Bluetooth_profiles

Gnome, there is one you missed. An iPhone can connect to a Mac via Bluetooth to provide Internet connectivity to the computer via the phone's cellular link. A Wi-Fi-less wireless access point, if you will. Slow as molasses and chomping your data allocation like mad, but sometimes that's all you have at hand.