The mobile apps for iOS and Android work like Cortana on Windows 10. Users can ask questions and Cortana will look up relevant information.
However, some features you find on Windows phones are missing on iOS or Android. Toggling settings, opening apps and invoking Cortana hands-free by saying “Hey Cortana” is not possible on Android and iOS.
Better feature-set on Cyanogen´s Android mod
Microsoft's close partnership with Cyanogen has resulted in a deeper OS integrateion. On Cyanogen devices users can enable Cortana out of every app and system screen. Using voice activation, users can ask Cortana to toggle network modes, power down their phone and turn on Quiet mode.
Cyanogen's CEO Kirt McMaster believes that putting Cortana to Cyanogen will catapult the operating system to the mass market.
“When Apple launched Apple Music at WWDC, they showed the Siri integration with Apple Music. Siri doesn't power Spotify like that so we can do these kind of things with for example, integration of Microsoft's Cortana into the OS enabling natural language to power Spotify and other services.”
As of today, the Cortana app is only available in the U.S. and China for iPhones running in iOS8 and up and Android 4.1.2. Soon it will also be available on One Plus One powered by Cyanogen OS with the 12.1.1 over-the-air update in the U.S. later in December.
Source: Windows Experience Blog