As per the PF Act, Para 2, Clause (f), an Excluded Employee means:
(i) An employee who, having been a member of the Fund, withdrew the full amount of his accumulations in the Fund (in case the employee was a member earlier and withdrew his full amount from his account).
(ii) An employee whose pay at the time he is otherwise entitled to become a member of the Fund exceeds [Fifteen Thousand Rupees] per month. (If he was not a member earlier and his basic + DA is less than ₹15,000/-, then you should enroll for PF.)
Employees have an exemption in the above two cases. If both cases are not applicable to you, then you should enroll for PF.