Earning by comments will require you to have your own Blogs and Websites. You will then share these dedicated domains (Owned by You) in the comment window. If an option to add your URL or website is not available, then you do not include links. You contact the site support first and get permission to share your URL. Oh, and NEVER share affiliate links in comments.
Now, unfortunately, there are a lot of scams when it comes to GPT sites. So it’s best to stick with well known, trusted sites that have been around for a while. You don’t want to complete offers for a month then when it’s time to cash out your earning find out that the site no longer exist. Trust me, I have seen a lot of “here today, gone tomorrow” rewards sites.
In most cases, when it’s too good to be true…then it normally is. A good way to check would be to first analyse the site and ensure it is in fact indexed in Google. There is no such thing as “Instant Riches”. I agree with Satrap, if you want to make a lot of money online then you’re going to sacrifice the needed time. Making money online is an art, not a contest.