Hello Sandy. I'm Greg, here to help you with this.
Yes, you can use Windows 10 and 11 without activating, it just will not be able to be personalized with desktop backgrounds, colors and other items under Personalization settings.
If you have any WIndows 7,8 or 10 licenses you can use those to activate Windows 10/11 upgrade, even a Clean Install which is a much better install.
Once a Digital License is issues for Upgrade, it's permanent for the life of the device, and if it's a retail license the Upgrade inherits it's rights to move to other hardware.
Other ways here to get Windows 10 for free:
https://www.groovypost.com/howto/download-windo...
https://www.zdnet.com/article/heres-how-you-can...
https://www.reddit.com/r/buildapc/comments/6fdg...
But beware that cheap licenses are almost always bogus. There are no steep discounts in Windows 10/11 retail licenses. Always buy from a retailer who back all sales or directly from Microsoft Store app in WIndows.
Feel free to ask back any questions. Based on the detailed results you post back, I will have other suggestions if necessary.
______________________________________________
Standard Disclaimer: There are links to non-Microsoft websites. The pages appear to be providing accurate, safe information. Watch out for ads on the sites that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the sites before you decide to download and install it.