I want to explore Sitecore CMS more. However, I am not able to download any trial or free version of Sitecore. https://dev.sitecore.net/Downloads/Sitecore_Experience_Platform/100/Sitecore_Experience_Platform_100.aspx
Is there any community edition or free version provided by Sitecore?
On
As of December 12, 2020 there has been a change in how you can access downloads for Sitecore software. You no longer need the proper license or certification or even to login to download the software. You will still need a license to run the software, though.
Sitecore software is now available to download for everybody, anywhere in the world, no restrictions.
As you mention the Url for Sitecore download this is correct, but if you want to download you need to be certified for that. Once you have been certified the you get the Sitecore user detail for Dev Portal then you will get the option.