The Dynamic Email is an actual page on your website that you are able to send out as an email, so that instead of just receiving text, the email includes the background style, the header, and any layout style, including colunms, images, etc.

To access your Dynamic Email, go to Site Management > Email Marketing > Dynamic Email. (*Note: Some sites may say "Email:General," or if you have multiple Dynamic Emails, it may list the names of each Dynamic Email page.) This will open the Dynamic Email page. You will notice that it looks slightly different from the rest of your pages—this is because it is designed differently so you are to send it as an email. It works exactly like one of your other pages when it comes to adding content and sorting items. 

Once the page is ready to be sent, you can either send it using the Mass Email function or the Email Scheduler.