Testimonials come in many shapes and forms. Here are a couple of examples.

In a video

Pete Cohen. Keynote Speaker, Life Coach and Entrepreneur. Co-founder of Mi365.
I work for Pete on a regular basis, providing content for his Online Membership Service – Mi365 Elite – and have also collaborated with him on his highly successful Mi365 Journal, several e-books and regular LinkedIn articles.

Via a message

This arrived from one of my more recent clients last week when we were discussing content she needed for an upcoming event.

Screenshot - I think you are the answer to my prayers

From a customer feedback form