You can insert a Viralize unit only on a Wordpress site created on a domain/hosting of your own. You can paste the code in a widget, in an article or directly in php templates.
If you use a Wordpress plugin for Google AMP, remember to use the compatible Google AMP code that you find in the "Get code" window of each Unit.
Read more in the instructions indicated for your chosen format.
Unfortunately advertisements, including those from third-party advertising networks like Viralize, are not allowed on blogs hosted on WordPress.com or WordPress.org.
Learn more at WordPress.com Advertising Guidelines.