Since yesterday, Microsoft has been rolling out notifications to users on reserving an upgrade to Windows 10 when it’s available. I got mine yesterday.
This is a free upgrade, from the info I know. You might have noticed a Windows icon on the lower right hand side of your screen. Click on it and it will guide you to register to reserve the upgrade.
To check out the steps, click on this link: https://www.microsoft.com/en-us/windows/windows-10-upgrade
Just a note, if you are upgrading from Windows 7, you might lose some stuff you enjoyed in Windows 7 premium edition. For those using Windows 8.1 (the normal version), I don’t see much issue as it already does not come with some stuff (such as DVD playback). Click on this link to learn more: http://www.idigitaltimes.com/7-features-users-will-lose-windows-10-update-446140