Our contractor laws are general, yes, you need to be registered or certified for almost everything. There is a catch, or a no-mans land, on basically site work, that can be confusing. Anything (at one point, the numbers might have moved) contracted at more than $1000 must be a contractor, but which one? CUC, Certified Utility Contractor, that's for underground, but not necessarily for grading. "CGC", certified general contractor, is the catch all, and can do almost everything, including unlimited height, value, and occupancy, but is really a license for building a building...
Certified state licenses, every single one requires a background check, an ethics and financial tests, and then a skill/knowledge test on the license you are getting. With that, you must have insurance based based on the license.
Registered, that's a local city/county thing, at least at one point, some counties made you come to a county commission meeting, and stand up there, and for a lack of better terms "kiss the ring", tell them about yourself, and request permission from the "crown" to work in their fiefdom... and pay a small amount for the privilege