The Container element is used to hold other elements on the page. You can drop any other elements into a Container element; it can hold as many elements as needed.
This element's primary purpose is for developers to use as part of the initial build of your site, but you may find other uses for it, as well. For example, you may want to add a number of elements to a Container and then convert it to a shared element to use on other pages.
Container elements do not have any customization options beyond the common element settings.