Registration of trust or charitable institutions under section 12A/12AA certifies that the Income Tax authorities recognize the registered institution or trust as having been incorporated or established for a charitable purpose.
The effect of such recognition is that the respective institutions are exempted from paying income tax, subject to the satisfaction of certain other compliance requirements as per law.
Section 12A deals with institutions and trusts registered before 1996, and Section 12AA deals with institutions and trusts registered after 1996. The NGOs have to obtain a 12A certification to avail tax benefits, regardless of whether they are constituted as a society, trust or not-for-profit company.

Registration of trusts or charitable institutions under Section 80G does not provide any direct benefits to them. The trusts or charitable institutions register themselves under Section 80G to enable the donors who contribute to them to avail themselves of certain tax benefits on their contributions.
The registration under section 80G of charitable institutions is to incentivise their donors to make contributions. However, only the NGOs that have registered under both Section 12A and 80G are eligible for availing of government funding.

In order to claim exemption, a charitable or religious trust or institution, including an NGO, should make an application to the Principal Commissioner of Income Tax or Commissioner of Income Tax online in Form 10A. The procedure of applying for revalidation/registration are mentioned below:

Step 1: Log in to the E-filing portal of the IT department.

Step 2: Go to the ‘Income Tax Forms’ under the e-File tab.

Step 3: Choose the Form Name as ‘Form 10A’ and select the relevant Assessment Year from the drop-down list.

Step 4: Choose the ‘Prepare and Submit Online’ option in the submission mode.

Step 5: Fill in all the details required in the form and attach the applicable attachments.

Step 6: Submit the form using EVC (Electronic Verification Code) or Digital Signatures as required during return filing.

The NGO’s applying for registration/revalidation as per the amended provisions of Section 80G are mandatorily required to provide the details of their Registration number with the DARPAN portal of Niti Aayog.
The registration under Section 12A and 80G are also mandatory when the organizations intend to receive or receive any grant or assistance from the Central Government or State Government.

The following are the documents that need to be submitted while applying for revalidation:

Self-certified copy of the incorporation document of Societies/Trust
Self-certified copy of the registration with the Registrar of Companies or Registrar of Societies or Registrar of Firms or Registrar of Public Trusts, as the case may be
Self-certified copy of registration under the FCRA [Foreign Contribution (Regulation) Act], 2010, if the applicant is registered under the respective Act.
Self-certified copy of the existing order of registration under section 12A/12AA/12AB, as the case may be
Copies of the annual accounts for a period not exceeding three years immediately prior to the year in which the application is made, in the case of existing entities
Where the income of the organization includes the profits and gains of business or where a business undertaking is held by the organisation under the provisions of Section 11(4A), copies of the annual accounts and audit report under Section 44AB for three years immediately prior to the year in which the application is made
Self-certified copy of the documents showing/evidencing modification or adoption of the objects
Notes on the activities of the trust or institution
The details of the DARPAN registration, if the organization is registered on the DARPAN portal.

12AA & 80G Registration