One of the features of the April 2018 Update for Windows 10 is Nearby Share, which lets users easily transfer files from one Windows 10 PC to another.
During a session at Build 2018 Microsoft also confirmed the feature is supported from Android handsets, allowing users to send files and links from their Android devices to Windows 10 PCs.
The feature was demonstrated in the context of its integration into apps via adding the Project Rome SDK into your iOS or Android app.
The feature uses Bluetooth to detect PCs and then decides automatically whether WIFI or Bluetooth should be used to transfer the file, depending on whether the devices are on the same network or not.
Microsoft did not, unfortunately, confirm whether this feature will be part of the general share contract on iOS or Android, however, but we assume this will eventually become available. Microsoft did confirm if users will be able to share to Android devices using Nearby Share in the near future, which appears to be the one missing piece of the puzzle.