Understanding PF Obligations: When Should Employers Start Contributions for New Hires?

I want to know if a professional (lawyer, CA, architect, etc.) while employing a person in his trade has to pay PF from the appointment date or after the confirmation period. What is the timeline for considering such probation as per laws? Is it necessary to pay PF at all when one hired turns an employee for such purposes?

If a lawyer's firm is covered under the PF Act, then the employee has to be covered under PF from the first day.