Stairway NEC Codes
If the stairway has 6 or more steps to get to the next floor, then at least one lighting outlet is needed. A switch for the light is needed at each floor level & landing level that includes an entryway.
Disclaimer: These codes are based on the NEC (National Electrical Code) 2023 edition and are provided for general reference. Local jurisdictions may have additional requirements. Always consult a licensed electrician and your local building department.