Hi, Juan. The only two ways to terminate Cortana are as follows, first, you can terminate Cortana through the Task Manager as some have said, or you can terminate it through the settings window as follows,

To Terminate Cortana

1. Open Windows Settings with Windows key plus I.

2. TAB to the list of Settings categories.

3. Right Arrow to Apps, and press ENTER.

4. TAB about nine times to the list of apps.

5. Arrow down to Cortana, and press ENTER.

6. TAB to Advanced Options, and press ENTER.

7. TAB to the Terminate button, and press ENTER.