Section 6(1) of the RTI Act, 2005 lets you apply in writing or electronically, in English, Hindi or the official language of the area, to the Public Information Officer of the authority holding the record. A plain sheet of paper is legally sufficient. Some states and ministries publish their own form; where one exists it is convenient, but its absence is not a valid ground for rejection.
What decides the outcome is the wording. The Act gives you access to records — documents, file notings, orders, registers, samples and data already held — not to explanations or opinions. Section 6(2) expressly bars the PIO from asking why you want the information. The application fee is Rs 10 for central authorities; state fees and payment modes vary.