If you are hosting your own blog powered by WordPress:
You can add the Certify Code to your site by installing the Alexa plugin and adding your site’s Certify Code to it.
If you have a blog hosted on WordPress.com:
Unfortunately, wordpress.com does not allow you to add javascript to a site. You need to be able to add javascript to your site in order to get your site’s metrics Certified on Alexa.
We recommend contacting wordpress.com and letting them know that you are interested in adding Alexa’s javascript code to your site.