In the U.S., nail technicians must be licensed by their state board — and rules differ from state to state.
Most states require completion of an approved training program (hours vary), passing a written and practical exam, and renewing your license periodically. Some states require displaying your license at your station.
Keep your license active, know your state hour and renewal requirements, and keep records of any continuing education. A current license is often the first thing salons check when hiring.