Sections are Divi’s largest organization element and are used to contain collection of rows. You can think of them as horizontal stacking blocks that group your content into visually distinguishable areas. In Divi, everything you build starts with a section.
This is a native module that comes with Divi for free. To add this module to your page, simply select the Sections module from Divi's module list. This module can then be fully customized using Divi's wide range of design settings.View Module Documentation
Structural elements are used to organize your content elements using horizontal and vertical contains such as rows and columns.