Microsoft Windows' virtual assistant app Cortana is now available in select iOS and Android devices. The Cyanogen-based OnePlus One smartphone is also getting this new feature.

According to Asia PC Mag, Cortana is now available for download from Google Play for Android mobile devices and from the App Store for iOS. Windows Blog reported that Cortana App is currently compatible in China and North America for iPhones running on iOS 8 or newer firmware as well as Android devices running with at least Android 4.1.2 mobile OS.

Meanwhile, OnePlus One owners can expect the arrival of the Siri-like virtual assistant app later this month. More Cyanogen-based devices are expected to get Cortana in the future.

For OnePlus One owners excited to try out the app, PC Mag's report noted that Cortana will be available for download on the smartphone via over-the-air (OTA) update. Since Microsoft and Cyanogen previously entered into a partnership, Ars Technica noted that a special version will be available for OnePlus One smartphone.

For instance, the Cortana app for Cyanogen-based devices will have features not found in the regular Android app version. One of these is "Hey Cortana" voice activation support for any screen and not only with the home screen.

"In addition, as a result of our close partnership with Cyanogen, we created a more integrated experience to enable Cortana's voice activation 'Hey Cortana' on Cyanogen devices so you can call on her while on any screen or when you're immersed in an app," explained Marcus Ash, the Group Program Manager of Cortana, as posted on the Windows blog.

Furthermore, Cortana on Cyanogen devices allows users to ask Cortana to turn off the smartphone and toggle network modes. Cortana can also enable Quiet Mode, which means notifications, alarms and calls will all be muzzled.

iOS and Android support for Cortana does not offer "Hey Cortana" functionality as well as the ability to toggle settings and open apps. However, users can set a location-based reminder on one device suchas your PC and then have it prompt on your smartphone once the user arrives at the specified location.

Another feature to look forward from Cortana is having missed call notifications. "With the Cortana app, get a missed call alert on your Windows 10 PC and let Cortana send a text back letting them know you'll call them later - all without leaving your PC," Ash revealed.

Below is a comparison video from Android Authority's YouTube channel talking about the three most prominent virtual assistants available today, namely, Siri, Google Now and Cortana: