My Mother received this certificate when she was 13 1/2 for completing the advanced course in the Palmer Method of Business Writing. The Palmer Method of penmanship, popular in the early 20th century, involved muscle motion, speed and plainness. As you can see, there was nothing plain about Mom! February 23, 1939.
The handwriting at the top of the page is from the Palmer Instruction material which I found on the internet. The practice sentences said: "It is not so much the amount of practice, as the kind of practice that counts. It is the constant effort to acquire precision that leads to success in writing."
The certificate is an actual photograph of the one Mom received. The original is big and has pretty pink and blue ribbon attached to the seal.