The Post Content module is in the Post modules category, which appears only when you're editing a Singular-type themer layout in Themer. It creates the content area in the Singular Themer layout, and it displays the content that authors type into the native WordPress text editor.
WordPress has only one content area. Although you can add more than one Post Content module to a Singular themer layout, the content from the native WordPress text editor will appear in every place you add it, so you'll have duplicated content.
The only settings available for the Post Content module are those on the Advanced tab, which means you can customize margins, responsive layout, visibility, animation, and assign an ID or class name.