If you have a licensed Windows 7, 8 and 8.1 you can upgrade to Windows 10 in the following ways.
1. Reserve in the Get Windows 10 app
Click on Get Windows 10 app, which should appear as a small Windows icon at the right side of your taskbar.
Click “Reserve your free upgrade” in the app when it opens. Enter your email if you want confirmation of your reservation.
You’ll get a notification after July 29 2015 once Windows 10 is downloaded to your device. Install it right away or pick a time that’s good for you.
2. If you do not have the Get Windows App you can upgrade by doing the following
On Windows 8: Go to PC Settings and then click on Update and recovery on the left. Click on download or install to update your computer.
On Windows 7: Go to Windows Update, click on Check for updates, select all updates and click Install updates.