We can get a full version of Windows 10, not a trial for free, Only thing you need to a faster internet connection
to do 3GB download. You have one year to upgrade Windows 10 from the release date.

The offer is valid only for qualified Windows 7 and Windows 8.1 devices, and they exclude some editions like Windows 7 Enterprise, Windows 8/8.1 Enterprise, and Windows RT/RT 8.1

Their lawyers made us say this:

Windows 10 Upgrade Offer is valid for qualified Windows 7 and Windows 8.1 devices, including devices you already own. Some hardware/software requirements apply and feature availability may vary by device and market. The availability of Windows 10 upgrade for Windows Phone 8.1 devices may vary by OEM, mobile operator or carrier. Devices must be connected to the internet and have Windows Update enabled. Windows 7 SP1 and Windows 8.1 Update required. Some editions are excluded: Windows 7 Enterprise, Windows 8/8.1 Enterprise, and Windows RT/RT 8.1. Active Software Assurance customers in volume licensing have the benefit to upgrade to Windows 10 enterprise offerings outside of this offer. To check for compatibility and other important installation information, visit your device manufacturer’s website and the Windows 10 Specifications page.

Here is how we can Get Windows 10 for free

We have to reserve our free upgrade to get it, For that we have to use the Get Windows 10 App which is found at the right side of the taskbar as a small Windows. If you don’t have that please see this link Windows 10 Help for more information. When you have completed your reservation it will download Windows 10 when available.

Open Get Windows 10 App and enter the email to get the confirmation of the reservation and you can cancel the reservation at any time, if you don’t like it.

This will gives you the notification when Windows 10 upgrade is ready for you