In Windows 10, Microsoft helpfully put a lot of major privacy settings in one location. Go to Start >> Settings and select Privacy.
You'll get a long list of areas from "General" and "Location" to "Contacts," "Calendar" and "Feedback." You can poke around each one to see what it controls and shares with Microsoft. However, there are a few you'll want to do right away.
1. Cortana: Getting to know you
Cortana is Microsoft's digital personal assistant. It's designed to learn about your movements, browsing habits, contacts, calendar and more.
That way, it can give you the information you need before you ask. Of course, that means it has to learn a lot about you.
If you don't think you'll use Cortana, you can turn her off completely. Simply click the Magnifying glass icon in the taskbar and go to the gear icon.
In the Settings, you can switch Cortana off, and there's a link to manage what she already learned about you. You can also stop Bing from recording information about you to improve your searches.
Of course, you can check to make sure that she really isn't still learning about you.
Back in the Privacy screen, under "Speech, Inking & Typing" find "Getting to know you." This controls whether or not Cortana is learning certain things about you. Make sure it's off.
Once you're done with that, keep looking through the Privacy area for more things you aren't comfortable with.