In case if you'll need to use Divi modules anywhere else outside main content in your pages you can copy the shortcodes that Divi generates and add them to the theme files or anywhere you need.
Each Divi item generates a shortcode pair . For example section module is present by this pair: [et_pb_section] [/et_pb_section] . Generally, sections contain some parameters, so a real shortcode looks like this:
[et_pb_section background_color="#7cda24" border_width_all="3px" width="57%"] [/et_pb_section]
Sections contain Row and Rows contain Modules. Here are some examples of how other shortcodes look:
A Row: [et_pb_row _builder_version="3.23.3"] [/et_pb_row]
A Module (Text module in this case): [et_pb_text _builder_version="3.23.3"]Your content goes here. [/et_pb_text]
By default, the shortcodes are not visible. To get the shortcodes, you can follow this guide:
Create the layout or add the module you want to get the shortcodes from.
Save the changes and Activate the default WordPress theme or any 3rd party theme. If you are using Divi Builder Plugin, make sure it's disabled at this point.
Go back to the page where you created the layout earlier and refresh the page. You will see the shortcode on the Front End / Backend.
Here is a screencast:
Once you got the shortcodes, you can add them to the php files using the standard WordPress function called do_shortcode.
An example is:
<?php echo do_shortcode('[ADD DIVI SHORTCODES HERE]');?>