ITR return forms are attachment less forms and, hence, the taxpayer is not required to attach any document (like proof of investment, TDS certificates, etc.) along with the return of income (whether filed manually or filed electronically). However, these documents should be retained by the taxpayer and should be produced before the tax authorities when demanded in situations like assessment, inquiry, etc.
As discussed above, no documents are to be attached along with the return of income, however, in case of a taxpayer who is required to furnish a report of audit under section 10(23C)(iv), 10(23C)(v), 10(23C)(vi), 10(23C)via), 10A, 10AA, 12A(1)(b), 44AB, 44DA, 50B, 80-IA, 80-IB, 80-IC, 80-ID, 80JJAA, 80LA, 92E, 115JB or 115VW or to give a notice under section 11(2)(a) shall furnish it electronically on or before the date of filing the return of income.
Source: Income Tax India’s Official Website