GRE: Postgraduate Record Examination, that is, Postgraduate Entrance Examination.
The former is an English proficiency test for living in a foreign country, and the latter is an academic English proficiency test. These two exams are the only way to North America. This is internationally recognized. What do you apply for this exam? Is it studying abroad? International exchange? If you don't take the exam, you don't have to fill it out. Generally speaking, CET-4 and CET-6 are not recognized outside, but you can say that your English is very good in your resume or personal ability, and there should be no specific place to fill in.