An Arkansas contractor taking work in North Carolina deals with the same four questions everywhere: who licenses the trade, when a licence is actually required, when workers compensation kicks in, and where the business registers. Below is North Carolina's answer to each, with the agency's own link.
Licensing
North Carolina Licensing Board for General Contractors
State general contractor license required to bid or build any project costing $40,000 or more (G.S. 87-1, verified at ncleg.gov). Licenses issued by the NC Licensing Board for General Contractors.
Workers compensation
North Carolina Industrial Commission
Businesses with three or more employees must carry coverage; radiation work requires it regardless of count, and contractors can be liable for uninsured subcontractors' employee injuries.
Business registration
North Carolina Secretary of State, Business Registration Division
Tax registration
North Carolina Department of Revenue
https://www.ncdor.gov/taxes-forms/business-registration/online-business-registration
New hire reporting
Most states require newly hired employees to be reported within a short window of their start date.
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Starting or running the business itself is covered in the contractor business guide. Arkansas licence records for Benton and Washington counties are in the contractor directory.