The following steps explain how to turn on Personal Hotspot (tethering) on Apple iOS devices.
In iOS 6 and Above:
Select Personal Hotspot.
Toggle Personal Hotspot to On
In iOS 4-5:
Choose Personal Hotspot.
Toggle Personal Hotspot to On.
To Connect to the Personal Hotspot
Select the name of your iPhone from the Wi-Fi settings on your computer or other devices.
Enter the Wi-Fi Password displayed on the Personal Hotspot screen.
Make sure the other Bluetooth device is discoverable.
On your Apple device, tap Settings.
Pair the two devices.
Connect your iPhone to your computer with a USB cable.
Choose iPhone from the list of network services in your settings.