Dear Friend,
It is certainly mandatory to deduct PF and other benefits, provided all are within the criteria of laid-down rules. It is not okay to simply pay basic salary and travelling allowance to the employees. The employees should be treated as a part of the organization. As for salary slips, it is proper to issue basic salary, DA, city allowance/HRA, TA particulars if necessary, CCA, Medical allowance, and in some cases, worked out uniform allowance, education allowance, etc. Deductions like EPF, loan deduction, etc., should be reflected. When you are referring to a small private/partnership firm, these items should be reflected. Yet, it is better to be good rather than a mockery.
A typical small firm reflecting exploitation of employees for the benefit of the firm.
Best of luck.