adsense and your site
You need to create a web site on which you will paste the google adsense code. This may sound simple, however there is a whole science that you need to follow, if you want to be successful.
1. The topic of your site is most important. You need to attract many visitors that may click on adsense ads. The popular topics have a lot of competition, and there is the rub!
2. The structure of your website is important. I must be in accordance with SEO (search engine optimization) standards.
3. Your web site must be easy to find by users. Even the best site is useless unless it can be found easily, for example in Google search. Go to Google Search Console, create an account, add your site and spend time in mastering the science of search console.