Certificate Programs are programs that can lead to credentials that will enable you to apply for certain jobs. Basically it will give you an advantage over someone that doesn't have the credential. Some people get a credential so they can get a better job to help them while they are continuing on to an Associates or Bachelors degree.
A registered apprenticeship is a Department of Labor/Office of Apprenticeship recognized training pathway. The goal is to get the National Occupational Credential so that you can travel to various job sites.
There are over 1000 registered programs that include on-the-job training along with related instruction (140 hours of schooling/year)