Do you have to go through a formal Six Sigma training program through your company if you want to get Six Sigma Green Belt certification, Six Sigma Black Belt certification, etc., or can you do it on your own through an outside provider? I want to be

Do you have to go through a formal Six Sigma training program through your company if you want to get Six Sigma Green Belt certification, Six Sigma Black Belt certification, etc., or can you do it on your own through an outside provider? I want to become a Six Sigma Black Belt, but I am between jobs and would like to boost up my credentials.