Detailed answer
ITR-1 is usually for resident individuals with salary or pension, one house property and simple other income within the notified limits.
ITR-2 is commonly used when there are capital gains, foreign income/assets, NRI/RNOR status, multiple house properties or other schedules not supported by ITR-1.
ITR-3 is commonly used for business or professional income with regular books. ITR-4 is for eligible presumptive taxation cases under provisions such as 44AD or 44ADA.
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