Fast, easy and fun to stay on top of work & life with your personal assistant Cortana! Bring your smart digital assistant to your phone to help keep track of the important stuff wherever you are, across your devices.

Cortana keeps an eye on your calendar, so if traffic is a mess and you need to leave early to make that meeting, Cortana’s got your back

If you need to find a fast answer or search for info on a flight or package, just ask. If you’re working on a task, like a budget, she can support you.

Like any smart voice assistant, Cortana will find all kinds of info, give you weather and traffic updates and help you search, but Cortana is a truly personal assistant who gets to know you better all the time—so she can help track and find the things you’re passionate about, like your favorite artist or sports team, and give you better recommendations and updates.
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how to use  
step 1: first createa microsoft accoutnt
             if not have a microsoft account so create a account and               sign in
step  2: you show this window

now you easily operate your mobile command through.

how to download this app :

that information is in my 1st post