Cortana is a virtual assistant bundled with Windows 10. Cortana appears as a search box or an icon on the taskbar and comes with tight integration with the Search feature in Windows 10. Signing in to Cortana with your Microsoft account allows it to keep track of what interests you, save your favorite places to its Notebook, collect notifications from other devices, and sync your data between all your devices with Cortana enabled.
Here are the screenshots of the new user interface of Cortana:
The Cortana - Beta app, when installed, replaces the current version of Cortana. It is available to Fast Ring Insiders. The new version released is 1.1907.5724.0.
By placing Cortana in the Store, Microsoft will be able to update it more frequently. Also, this can potentially give the end user the ability to install Cortana like any other Store app. Check out the app page on the Store here:
Source: Aggiornamenti Lumia