Look online at the curriculum of the Doctoral and Ph.D. programs that interest you. If you do not know the website address of the school you can conduct a search through a search engine such as Google. Most schools have their curriculum and course descriptions online, which makes it easy to compare program requirements and descriptions.
Ask the admission office at the college to mail you a course directory. Each school has its own program requirements. This include taking comprehensive exams (called orals), taking graduate level courses, attending residency in addition to writing a dissertation or doctoral study for completion of their program. Also, inquire about the school's accreditation and requirements.
Contact an admissions representative or enrollment adviser at the college or university to learn more about the program requirements. They should be able to discuss how their program differs from others. Some colleges offer both Ph.D. and Doctoral programs, and the school representative would be able to answer questions about the different requirements for each program. Some schools will allow some of your Master level courses to transfer into your Doctoral or Ph.D. program.