The personal statement should be about 1 page and reflect why you want to pursue graduate school or your particular program, your personal/professional goals, any previous research experience, research interests, etc.
Program: Mechanical Engineering PhD
https://bulletin.case.edu/schoolofengineering/mechaeroeng/#graduatetext
https://engineering.case.edu/emae/graduate-program
All applicants go through a series of tests that check their level of English and knowledge of formatting styles. The applicant is also required to present a sample of writing to the Evaluation Department. If you wish to find out more about the procedure, check out the whole process.