Bluetooth is a quick and convenient way to share a file between two devices. The ubiquity of Bluetooth means you can use this method to share with a vast array of products, from other Windows devices to old feature phones. While Wi-Fi sharing is faster and more robust, it doesn't match Bluetooth for compatibility or simplicity.
Sending files over Bluetooth is a straightforward process in Windows 10. First, make sure your device's Bluetooth is turned on – the "Bluetooth" tile in Action Centre (Win+A) should be highlighted in your system accent colour. You'll also need Bluetooth to be enabled on the device you're sending the file to.
Next, make sure your devices are paired together. If you haven't shared files between them before, open the Windows 10 Settings app (Win+I) and click the "Devices" category. Here, press the "Add Bluetooth or other device" button and choose "Bluetooth" in the popup which appears. You'll need to ensure your second device is visible and accepting new connections – refer to its instructions for details.
You should see the device show up after a few seconds. Tap its name to make the connection. You may need to acknowledge a PIN confirmation before the pairing is completed.
To send files to the device, right-click the Bluetooth icon in the Windows system tray. It might be buried in the overflow menu – click the upward-pointing arrow if you can't see it straightaway. From the right-click menu which appears, click "Send a file."
A wizard will appear to guide you through the sharing process. First, select the device you want to send your file to. The device you paired earlier should show up immediately, so click it and press "Next."
You can now choose the files to send. You can add multiple files from anywhere on your PC. Just remember that Bluetooth's low data bandwidth means it's best suited to the sharing of small files – otherwise, you'll be waiting a long time for the transfer to finish.
When you click the "Next" button, Windows will start to send the files to your paired device. You'll need to ensure its Bluetooth is turned on and connected to your PC before starting the transfer. You may also need to confirm a prompt on the receiving device to accept the incoming files; refer to its documentation for details.
A progress bar is displayed for each file, so you can monitor the status of the operation. When you see a success screen, all of the selected files will have been stored onto your paired device.