To use AdSense, you must have access to the HTML source code of your site. You need to be able to place AdSense code between the <head> tags of your pages. If you sign up with a site you don’t own (e.g., www.google.com), AdSense won’t be able to verify that you’re the site owner and AdSense won’t activate your account.
Note: You may only place AdSense code on a site that complies with the AdSense Program policies.