You can add new testimonial through Testimonials → Add New Testimonial in the WordPress Administration Panel.
Additional Testimonial Options
Testimonial Options are found below the title on the Edit Testimonial page. If the Testimonial Options are not visible, make sure they are checked inside the Screen Options area at the top.
Here you can write the name of the person in the testimonial.
Insert the photo of the person who wrote the testimonial.
Insert the Company name.
Company site URL
Insert URL of the company.