An Arkansas contractor taking work in South 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 South Carolina's answer to each, with the agency's own link.
Licensing
SC Department of Labor, Licensing and Regulation: Contractor's Licensing Board and Residential Builders Commission
Contractor's Licensing Board: general and mechanical license required when commercial job cost exceeds $10,000 (raised from $5,000 by 2023 Act 69). Residential Builders Commission: builder license over $5,000; residential specialty registration over $500.
Workers compensation
South Carolina Workers' Compensation Commission
Coverage required with four or more regular employees; exempt if fewer than four employees or prior-year payroll under $3,000 (SC Code 42-1-360).
New hire reporting
We could not confirm a new hire reporting site.
Most states require newly hired employees to be reported within a short window of their start date.