PAN is the most important document for filing ITR. It is also mandatory for individuals to link PAN with Aadhaar.
If you are a salaried individual, you need Form 16 from your employer to file ITR.
For non-salary income such as interest, dividend and rent, you will need TDS certificates that mention the tax deducted at source.
For interest income on which TDS has not been deducted, such as interest on post office schemes and government bonds, you’ll need interest certificates.
If there are any capital gains or dividends from shares and mutual funds, they must be reported on the ITR. Keep your capital gains statement handy while filing ITR.