You have to conduct a meeting of the proposed NGO. In the meeting, you have to mention the aim, objective, president, vice president, treasurer, advisor, members, etc. You have to pass the resolution of forming the NGO, and all members must sign it with the date and the proposed name of the NGO.
Thereafter, you have to go to the Charity Commissioner/Assistant Charity Commissioner's office and buy the form (it costs 5 or 10 Rs).
According to the performa, you have to complete the following documents:
1) Power of attorney in the name of the president/secretary
2) Consent letter of all members/trustees
3) Resolution
4) Bylaws of the NGO as per the performa (Draft an MOA)
5) NOC from the premises owner of the address in which the NGO is to be registered
6) Declaration of all movable and immovable assets of the NGO on a 20 Rs non-judicial stamp
7) Other documents as required
Afterward, you have to apply to the same office under the Registration of Societies Act 1860 and Public Trust Act of respective states (In Maharashtra, it is Bombay Public Trust Act 1950/section 25 of the Companies Act).
You should receive your registration certificate within 1 month for a Society and within 2 months for a Trust, and you will get a registration number.
If you want tax exemption, as soon as you get the registration number, apply to the Income Tax department for tax exemption under section 80(G).
In the case of Foreign Funding, then one needs to apply for FCRA.