MIT supplementary document question?

<p>For the supplemental materials, my little brother noticed that a requirement where "All letters must be typed or written on official school letterhead and signed by the evaluators." What does it mean with the official school letterhead? Does it want MITs? or does it mean the company of recommendation? Or something else altogether?</p>

<p>They want official letterhead from the organization of the person who is writing the recommendation.</p>