The Custom Section Field is a nifty field that can be added to any Module or Content Definition. This field can be set up and used in many ways, as it can contain any HTML code you wish.
To test out the Custom Section Fields, let's first add it to a Module Definition:
Scroll down to the Field Properties Area and you will find an area where you can set the content for the Custom Section, Let's add some HTML:
Now let's add this module to a Page, and see how it turns out: