You can still upgrade Windows 7 to Windows 10 for free.
Originally when Windows 10 came out, Microsoft made what they called a limited time offer to be able to upgrade Windows 7 to Window 10 for free. That was several years ago and the time it was to expire has long passed
Microsoft has not removed the offer from the Internet, and I used it just a couple weeks ago to upgrade a computer that was still running Windows 7 to Windows 10.
Why should you upgrade to Windows 10 from 7? The first reason is Microsoft is no longer supporting Windows 7 which means they are not releasing updates for it, including updates to patch security holes. This means it is easy for hackers (attack agents) to break in your computer and steal information. The second is that newer versions of software may no longer work on Windows 7 which leaves you with the older version that may not have as many features and is not as secure.
Windows 10 has menus like Windows 7 so not a major learning curve. If you liked Windows 8 with its large icons instead of menu or like how that appears on your phone or tablet, Windows 10 will also let you get in that mode instead called Start Screen.
Upgrading is a pretty simple process. You will go to the link https://tinyurl.com/w7to10 (that is a short one I generated that really goes to a link over 1000 characters long using TinyURL) and then following the process and no difficult questions to answer. However, the process will likely take hours to run so be patient.
Before you do it, I would encourage you to first run a program to get al your keys to your programs. In doing the update Windows may lose the keys or the programs may want reactivated and need keys to run again. After you run it and it shows the list, print it, or could write down if short, so you have when you finish the update. One program that has worked well for me is produkey