The ITR-3 form is specifically designed for individuals and Hindu Undivided Families (HUFs) with income from business or profession, excluding those eligible for ITR-1, ITR-2, or ITR-4. The form includes sections for general information, income details, deductions, tax computation, and verification, and requires various financial documents for accurate filing. The due date for filing ITR-3 is July 31st for non-audit cases and October 31st for audit cases, with penalties imposed for late submissions.