You can still upgrade to Windows 10 for free in case you have missed all the other opportunities. The last chance to upgrade was end of December when the free upgrade to users with assistive technologies ran out, or this was the theory.

You can still download the Windows 10 ISO, mount or extract it and install Windows from there. You can use your existing Windows 7 or 8 product key to install and activate Windows. You can do an in place upgrade and keep all your settings or a fresh install.

Download the ISO here:
https://www.microsoft.com/en-us/software-download/windows10ISO
Microsoft has made one ISO for both Home and Professional so that makes it nice and simple.