On your phone, go to Settings, then open Network & Internet or Other networks and connections. Select Personal Hotspot or Hotspot & tethering, choose Other sharing mode if it appears, and enable Share phone network via Bluetooth.
Next, pair your phone with the device that needs internet access. Confirm the pairing request on both devices and make sure Bluetooth remains connected. On the second device, open its Bluetooth settings, select your phone from the paired-device list, and turn on Access network or Internet access. The second device can then use your phone’s mobile data connection.
Menu names may differ by device model and software version. Mobile-data charges may apply, so check your plan and disconnect Bluetooth tethering when it is no longer needed.