The unveiling of Cortana by Microsoft was done as a part of Windows 10. The digital application will be a part of Microsoft Edge browser and Windows 10. It was revealed by Joe Belfiore that Cortana will be part of the cross-platform as a part of Microsoft service.
It is not surprising since the company based in Redmond has moved fastly in order to bring the services to Android and iOS and for that purpose, Cortana is the next leap taken. With the use of Cortana on Windows Phone, you could use to track flights, setting of reminders for location by using geo-fencing, checking of sports scores etc. Use of Cortana could help in performing actions in other applications which is not possible with other systems that are third party. There is deeper interaction of activation of voice in the use of Cortana.
With the use of Windows 10, digital assistant will be the main at the center and front. But Microsoft do have knowledge that Cortana does not have market penetration as expected. It could be used at any place you are only. Using this capability is a real good plan. There are odds that the application will not be changed by Google in the coming years to come. But it will allow you to get reminders when you are going to the store and the phone will give you message whenever you are near to it, even if you are not near in the ecosystem i.e 100%.
The other side of the story is that Windows 10 will be working with iOS, Android or even Windows Phone. When you choose the application companion, you could choose the type of smartphone you wish to have and the application will allow you to download the application of Microsoft which could help in the synchronization of the world desktop with the phone.
If you have the application, objects like OneDrive can be used to share and store files. OneNote can be used for Office, Skype, notes and other forms of documentation and communication. Also, you could have Outlook that is installed and used for email purposes. It all depends on how important these are that is based on if the applications are used for services. If the services are used, then you need to have the applications. This is basically used for promotion of services on various platforms.
On Windows 10, the newly available application will be Phone Companion application which will be made available through Program Insider. Most of the application will be made available on Android and iOS. But Cortana will be available by June end in Android and in iPhone, by the end of the year. You could get the updated Music Application by the end of June of July for sure.