If you are a distance educator, how did you prepare for your job?

I am interested in working in the future as a distance learning educator. I currently have a master’s degree in educational media, and I have been teaching school for 25 years (elementary, middle and high school.) I consider myself a K-12 “generalist.” I am interested in working, teaching online courses to elementary, middle and high school students in remote locations. Is there a degree program or certification that will prepare me for this job? I really don’t need another college degree.