Answer :
This form of giving evidence is known as Testimony.
While giving a speech on the benefits of shopping at local stores instead of malls, Megan quoted two of her friends. It helped her in making her speech more persuasive and convincing. It is basically a formal way of presenting a situation in terms of your own experience. It can be oral or written as well. This effective way helps people in understanding, remembering, and sharing the experience with others.