Cortana is an intelligent personal assistant created by Microsoft for Windows Phone 8.1 and Windows 10 (where it now supersedes Bing Mobile), Microsoft Band, Windows 10, and coming to iOS, Android, and the Xbox One.Cortana was demonstrated for the first time at the Microsoft BUILD Developer Conference (April 2–4, 2014) in San Francisco. It has been launched as a key ingredient of Microsoft's planned "makeover" of the future operating systems for Windows Phone and Windows.