Dear Vasu,
If you want details regarding PF and ESI, there are a lot of threads available on citehr. Additionally, you can also Google to find answers to your questions. However, please mention the salary structure, i.e., Gross salary for ESI, and Basic, DA, and retention allowance for the calculation of PF. Also, specify all the deductions your company is making under the head of deductions.
As for payroll, it is a process of documentation for paying salaries to employees. It can be done manually (using registers, etc.) or by using computers, which makes the process easier. For example, my company uses Microsoft Excel for this purpose. In this system, an employee's data is maintained, including Name, DOJ, No. of days worked in the month, Basic salary, DA, HRA, Conveyance allowance. All these details are used to calculate the gross salary, from which deductions like PF, ESI, telephone charges, among others, are made to arrive at the net salary. This information can be organized neatly in a single sheet. This is a brief overview.
Please be specific about your doubts so that we can assist you better.
Regards,
Shreekanth.P.R