If you have an Android phone and you have Windows 10 on your computer, you can project your screen from your phone onto your computer's screen with no extra apps no cables. These steps and the accompanying screen shots are from a Samsung Galaxy S6.
First, take your finger and swipe down from the top of your phone. Swipe down again and you'll see some of these built-in apps. Swipe to the right and what you're looking for is Smart View. Press Smart View with your finger and it's going to start projecting your phone.
Now go back to your computer. Type the Windows key and then type connect into box where you cursor is waiting at the bottom of the Start menu. After you type a few letters, the Connect app will be selected. Press enter to start it.
The Connect app will search for your phone's signal that is being projecting by Smart View. Your phone and your computer will look for each other and then connect. That's all. Two steps and we're already pretty much done. You've projected your Android phone screen on to a computer running Windows 10.