The Ph.D. is primarily directed toward students with an interest in developing research skills. Relevant careers include becoming a researcher, professor, or policy-analyst. The Ed.D. is primarily directed towards students who want to be change agents in education. Relevant careers include district or school leadership or educational consulting. Both programs are rigorous and well regarded. Students take some courses together. Your decision between which degree to pursue should be based on your ultimate career goals. 

The Ph.D. program is directed towards students who want to develop research skills, which are not necessarily required for a school principal. If you are interested in becoming a school principal, the Masters or Ed.D. programs are likely a better fit for the skills and knowledge you wish to develop to be a well-prepared leader. If you do choose to pursue the Ph.D program because you want to become a researcher and also give yourself the option of being a school principal, it is possible to complete the required Master’s-level courses during a Ph.D., but this would require extra coursework and is not the intent of the Ph.D. program. 

While a master’s degree is preferred for admission, it is not required. 

While the GRE is preferred for admission, it is not required

Yes you do as it is a university and grad school requirement English Language Proficiency Requirements

You can find that information here: International Applicants | The Graduate School  

You can request to work with a particular faculty member, however the faculty will work with each student individually to determine the best match.

Most full-time students earn the degree in 4-6 years.

The Ph.D. degree is designed to develop academic researchers or others interested in concentrated study in leadership, reform of educational organizations and systems, educational governance, finance and policy analysis, comparative education and related fields. The program emphasizes policy, theoretical and conceptual analysis, and empirical research. The degree is earned through successful completion of coursework, qualifying exams and a doctoral thesis. Most full-time students earn the degree in 4-6 years.