An Arkansas contractor taking work in Michigan 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 Michigan's answer to each, with the agency's own link.
Licensing
LARA Bureau of Construction Codes
No state license for commercial general contractors. LARA licenses residential builders statewide, plus electricians, plumbers, mechanical contractors, and boiler and elevator trades, through its Bureau of Construction Codes.
Workers compensation
Workers' Disability Compensation Agency, Dept. of Labor and Economic Opportunity
Required if you regularly employ one or more employees 35-plus hours per week for 13 or more weeks in the preceding 52, or three or more employees at one time (part-time counts).
Business registration
Michigan Dept. of Licensing and Regulatory Affairs (LARA), Corporations Division (not the Secretary of State)
Tax registration
Michigan Department of Treasury
https://www.michigan.gov/taxes/business-taxes/new-business-registration
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.