GRE stands for Graduate Record Examination
Prospective graduate and business school applicants from all around the world who are interested in pursuing a master’s, MBA, specialized master’s in business or doctoral degree take the GRE General Test. Applicants come from varying educational and cultural backgrounds and the GRE General Test provides schools with a common measure for comparing candidates’ qualifications.
GRE scores are used by admissions or fellowship panels to supplement your undergraduate records, recommendation letters and other qualifications for graduate-level study.
So I would first begin with what is GRE, and why is it required in the first place.
The Full form of GRE is Graduate Record Examination. It is required to add weight to your foreign application in different universities of the world. However, it is not compulsory for to all countries. For some countries it is obligatory to sit for the exam like USA, and for some, not so much, like UK. It varies from college to college as well.
Now, some myths regarding GRE is that it would help you get through colleges or scholarships without any other requirements which is absolutely wrong. It sure does add credit points to your application, which is why you should take it, but apart from that your APPLICATION is the most important of all. Only if the application gets accepted, you get into the college. In addition to that, your academic record, work experiences, internships, extra curricular activities and so on, add to it.
Coming to the last part of your question, surveys have it that mostly Engineers take this exam. Nonetheless, prospective graduates from all courses can take this exam. There is GMAT, which helps the MBA students in a better way. Nevertheless, they can sit for GRE as well. Hope this helps.