It is not compulsory, but why would you want to waste an opportunity to save money? It will help the employer save 8.33% of the employer's share paid to new employees.
Eligibility concept
1. The employee strength of the given month should not be less than the employee strength in the month of March of the previous fiscal year.
2. The employee should be a fresher, i.e., with no previous employment records in PF.
3. The employee should receive a salary (gross) less than Rs. 15,000.
If all the above conditions are met, then you can apply for PMRPY registration for the particular employee in the given month.