As of January 1, 2020: NJ law prohibits employers from asking applicants about their salary history (including wages, commissions and benefits).
Employers are required to use the updated 2020 W-4 form. Employees will need to provide more information than was required previously to complete the W-4 including: pay statements for the employee and, if married, the employee’s spouse; other sources of income; dependents for whom a certain tax credit can be taken; and the most recent tax return. The following is a link to the new W-4 form: https://www.irs.gov/pub/irs-pdf/fw4.pdf. The following is a link to the FAQs regarding the new W-4 form: https://www.irs.gov/newsroom/faqs-on-the-2020-form-w-4.
Also remember that under the Affordable Care Act, an employer is required to inform new employees within 14 days of hire whether the employer provides group health insurance. The model notices are located at the following link: https://www.dol.gov/agencies/ebsa/laws-and-regulations/laws/affordable-care-act/for-employers-and-advisers/coverage-options-notice.