The testimonial section is one of the best ways to promote your product or service.
Here’s how you add it:
First, add the right Module
New modules can only be added inside of Rows. If you are starting a new page, don’t forget to add a row to your page first. Learn more about Rows here.
Use the visual builder to add a standard section (the blue +) and then a section (green +) with a layout of your choice. The number of columns could be changed afterward.
Then add a Module Button to any part of the row.
Click the gray plus button to add a new module to your page.
Click on Testimonial

Content Tab
In Content, you can add Author Name: [enter name], Job Title: [enter title], Company Name: [enter company]
You can add the testimonials in Body
You can also add the Portrait Image URL: [upload 90×90 image]
In element
You can choose to show Icon or not.
Use Background Color: Choose the color or set to NO

Design
In the Design section, you can change:
Text Color: Light to Dark
Text Orientation: choose alignment
Body Font:
Body Font Size:
Body Line Height:

You can duplicate this module and re-design the others.

For more information: https://www.elegantthemes.com/documentation/divi/testimonial/