Employee contribution to PF is 12 percent, and an equal percentage is contributed by the employer. While EPF rules allow the employee to contribute up to 100 per cent of one's basic pay, the employer need not match the enhanced rate of contribution.
So approach your employer and give a written declaration of how much you would like to contribute above 12 %.
Employer can automatically arrange for deduction from your pay and remit the same to EPF Office.