To enable “Hey Cortana” feature, you need to do the followings.

*.Open Cortana homepage by tapping/clicking the search box right next to the Start button.

*.Hit the menu button at the top left corner of the page then select Settings.

*.In Settings page
You’ll see the option “Let Cortana respond when you say “Hey Cortana.” Just simply turn this option on and you’re done.

Because Windows 10 in general is still buggy, “Hey Cortana” may sometimes stop working.

You just need to log out and log back in to try again.
However, when it works, it works perfectly!

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