As per the provisions of the PF Rules, if the permanent strength (salary being paid regularly) of employees is more than 20, the organization needs to provide PF facility. To apply for the same, please approach the local EPF office, collect relevant forms and submit the filled-in application. It is not very cumbersome, and records that are needed are ~ P&L account, salary register(s), attendance register(s), extract of bank accounts, memorandum of association etc. There are many consultants, who can get this done for you by collecting a fee. The EPF organization may choose to visit your premises and demand to inspect all old records, so be ready for the same. Though you can restructure the CTC to accommodate the PF recovery, initially there will be a drop in take home pay of employees, which will become a reason for resistance from them.
All the best!