If you perform Financial Advisor services through ADP by being Hired by ADP, ADP would then pay you through payroll as their Employee.

If, on the other hand, ADP contracts with your business to have you consult with them and/or their staff as a Benefit to inform their employees, you sign a contract and get paid as an Independent business providing services to ADP, who is your Client. And you get paid Independently, as a Business to Business relationship. And if that is $600 or more, ADP will report that to the IRS and you through the use of a 1099-NEC form. That way, the IRS has been given notice to expect a Business Return from you when you file your own tax return. And you would report Gross Income; if ADP is not the only customer, then you would be reporting All income, not just that 1099-NEC.