Many jobs require an industry credential or certification to enter or advance within an occupation. Certifications are nationally recognized verifications of skill or knowledge attainment based on generally-accepted skill standards for an occupation.
Certifications usually include a combination of an examination, demonstration of skills, and/or experience requirements. Professional associations can be a great source for learning about occupations and their related certifications.
For more information check out:
CareerOneStop Credentials Center
CareerOneStop Certification Finder
Frequently Asked Questions About Data on Certifications and Licensing, Bureau of Labor Statistics