Modes of filing tax returns: paper, digital signature, electronic verification code, or ITR V physical verification. Return of income may be filed by paper, electronically under digital signature, electronically with an electronic verification code, or electronically followed by submission of a signed ITR V. If filed electronically without a digital signature, the taxpayer must sign two printed ITR V copies, mail one signed copy to the Income tax Department processing centre within the prescribed period, and retain the other copy.