Yes, an employee is allowed to contribute more than 12% of their basic pay in the PF fund. Any employee can increase his monthly contribution up to 100% of basic salary.
PF Deduction is made by employee as well as employer. An employer is not bound to increase the PF contribution, if the employee wants to increase it.
For example: There is an employee whose total (employee + employer) contribution for PF is Rs 1600. Both the employer and employer contribute Rs 800 each.
Now if the employee wants to double (24%) the PF contribution (as Rs 1600). It would be done, but the employer will continue to pay the same amount as before Rs 800, unless the salary of the employee is not revised/ incremented. The employee can benefit from double interest of PF contribution.
Get more information about PF and its deduction rules at
https://empxtrack.com/blog/esi-pf-statutory-compliance/