PF & ESI registration

Registration for PF and ESI is compulsory for the organizations who employes more than PF (20) people & ESI (10).
Small organizations which do not have 20/10 employees can also register themselves voluntarily.
Organizations once crossed the limit of 20/10 members must get registered themselves within one month of attaining the minimum strength.
Conclusion: Yes, voluntarily you can get the registration under PF and ESI.