As Butch indicated, there are many types of inspections and inspectors that perform the inspections.
Different organizations, such as AWS, API, and ASNT, provide training for people interested in obtining certifications in different fields. AWS provides training and certifications for the inspection of welds. API provided training an cetifiation for inspectors working in the petrochemical industry, ASNT provides training in nondestructive testing. NACE provides training and certifications for the inspection of paints and corrosion.
There are also independent organizations that provide training for different industrial sectors.
You can do web search to find companies and/or orgnizations that provide the type of training you are seeking.
Good luck.
Best regards - Al