With WordPress you can easily add your AdSense code to your blog.
In order to do this, firstly login to the administrative panel of your website.
Then, go to the Appearance -> Widgets menu.
In this page select to drag-and-drop a “Text” widget onto your registered sidebar.
Then you should add a title (in our case – Advertisement) and right under it the actual code that you have obtained from Google.
Finally, click on the “Save” button right under it.