Sections are the biggest building block in the Divi builder. Think of them as horizontal stacking blocks that can group your content.
Everything you build starts with a section.
Enter the Visual Builder, you can click the blue + button to add a new section to your page.
A popup will appear, you will have to add any of Divi’s three section types. These types include Standard, Specialty, and Fullwidth.
Section Content Options
Within the content tab, you will find all of the section’s content elements. For sections, these content elements are limited to background elements such as background images and videos.
To edit the size, hover your cursor over the bottom of the image (you’ll see the min. Height text appear), and drag down the border
Section Design Options
Within the design tab, you will find all of the section’s styling options, such as sizing and spacing. This is the tab you will use to change how your section looks. Every Divi section type has a long list of design settings that you can use to change just about anything.
Here you can adjust the padding of the section to specific values, or leave blank to use the default padding.
Control which devices your section appears on.
Disable your section on tablets, smartphones, or desktop computers individually.
Using Full-Width Sections
Full-Width sections give you access to a new set of Modules. These modules take advantage of the full width of the browser.
Add a new full-width section to your page,
Click the Add Modules button within the section to add a fullwidth module.
There is no concept of rows or columns, it will fill 100% of your page width. Fullwidth modules are a great way to add a visual break to the page!
For more information: https://www.elegantthemes.com/documentation/divi/sections/