Dear Shipra,
The Salary bifurcation or salary structure depends upon many basic factors like Organisation profitability, budget, future strategy, No. of employees, management approach towards employee welfare and benefits etc.
However, the main compulsory point is that the salary structure should not be less than the MW as defined by the appropriate govt.
You can pay over and above the MW. To make is tax friendly and enhanced "In Hand Salary" we use customized salary structure as per requirement. Fellow members have explained some basic concept and ideas related to Salary Structure.
Pls find attached CTC Calculator wherein two sheets attached (ESI Applicable and Non ESI Applicable).
Hope this will meet your requirement.