How to File RTI
Under the Right to Information Act 2005, every Indian citizen has full right to demand any information from the government if he/she desires to do so. The Government, as per the RTI 2005, is liable to provide the information demanded to the citizen. If the government authority from which information is demanded fails to do so, the government authority will be penalized.

Filing an RTI to a Central Government Department and approaching the Central Information

Commission

• Department Identification
  The first step to file an RTI would be to identify from which department the information has to be obtained.
• Writing the Application Properly
  The next step would be writing your RTI application in the prescribed format. Click here to know the format. Also, this format isn’t mandatory and you can submit your application on a plain paper as well. The language of the application can be Hindi or English. Similarly, the government can also respond in either language. You can check the Rules for filing an RTI with Central Government Departments here.
  Make sure that the questions you ask relate to only one subject; the application has a chance of rejection if you ask more than one questions in a single RTI Application.
• Make Payment of Fees
  As you might know, there is some amount charged for each RTI you file. Thus, to file an application to a central government department, attach application fee of Rs. 10/- in the form of Indian Postal Order.
• Send Application
  Once all the above mentioned steps are completed, send your RTI application via speed post/registered post and wait for the response. If you don’t get a reply within 30 days of sending the application, you can approach the central information commission.

Here’s a bit more detailed process about the same.