Bluetooth tethering is a method of sharing your phone's internet connection through Bluetooth.
To use it:
1. Go to Settings> Network & Internet> Hotspot & Tethering, and toggle on Bluetooth Tethering.
2. Enable Bluetooth for the other device, pair the device, and connect your phone to the WiFi with network access.
3. On your device, go to Settings> Bluetooth and tap the paired device.
4. Toggle on Internet access.
Note: Tethering works when your phone is connected to the Internet via mobile data or a WiFi network.