How enable adsense in wordpress

Adsense requires you to add your new website to their list:

To enable adsense in your wordpress website, you need to paste this code between the head tags:

<script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
<script>
     (adsbygoogle = window.adsbygoogle || []).push({
          google_ad_client: "ca-pub-6220266062998622",
          enable_page_level_ads: true
     });
</script>

You should also read this:

How to insert ad code in your WordPress site

Use this plugin:

Insert Headers and Footers