Certify is used only transitively. It carries a variety of meanings, but for the context in which this worksheet embeds the verb, , it means “to attest authoritatively,” “confirm,” and “to attest as being true or as represented or as meeting a standard.” A certificate is what one receives when the definition of certify has been met in practice.
If you find typos in this document, I would appreciate a notification. And, as always, if you find this material useful in your practice, I would be grateful to hear what you think of it. I seek your peer review.