For immigration purposes, the main job skill type or levels are:
- Skill Type 0: occupations related to management, such as factory managers, resort managers, or office managers.
- Skill Level A: professional occupations that usually need a university degree, such as chemists, veterinarians, or pharmacists.
- Skill Level B: technical occupations that usually require a college diploma or apprentice training, such as administrative assistants, firefighters, photographers.
- Skill Level C: intermediate occupation that usually need a high school diploma, such as truck drivers, travel guides, or receptionists.
- Skill Level D: labour occupation that usually only require training, such as dry cleaners, kitchen helpers, or receptionists.
You have to make sure you are using the 2016 version of the NOC. 2006 and 2011 versions also exist and there are differences with the 2016 version that is currently in use by IRCC.