Taxpayers in India can file their income tax returns (ITR) either online or offline, but they must ensure they have the correct documents ready to avoid mistakes. Essential documents include the PAN Card, Aadhaar Card (which must be linked to the PAN), and Form 16, which details salary and deductions. Other required documents are the Annual Information Statement (AIS), investment proofs, and a home loan interest certificate. The deadline for filing ITR for the financial year 2026 (assessment year 2027) is July 31, 2026, with a later deadline of August 31, 2026 for specific ITR forms. Taxpayers who miss the deadline can file a delayed return until December 31, incurring a penalty based on the delay duration. Choosing the correct ITR form is crucial, depending on the taxpayer's income sources. For any errors in the submitted ITR, taxpayers can file a Revised Return to correct them.