The Light Phone II includes Bluetooth (4.2), however, it is OFF by default.
You can access the bluetooth settings page by going to:
Settings > Bluetooth & Wifi > Bluetooth
You can also get to your bluetooth setting from within the Music or Podcasts tool.
To pair a new device, toggle ON bluetooth and then press PAIR NEW DEVICE. Look for the device you would like to pair to appear under "other devices" list. Click to select the device that you would like to join. If there is a code required you will be prompted to enter it.
Reconnecting to Known Devices
Once you've connected to bluetooth devices, they will be added to the home page of the bluetooth settings so you can re-connect to them in the future. If you previously used a device, it may even automatically reconnect if the device supports it. Otherwise simply click the device you'd like to re-connect, and then choose Re-connect from the options.
When a device is currently connected, the bluetooth icon indicates such. Also while in the Music/Podcast tool, if there is a device connected, the bluetooth icon is underlined indicating such.
Forgetting a Bluetooth Network
While connected to a Bluetooth device you can forget the device by clicking on that device from the known devices list. You will see an option appear to "forget the device".