Return filing obligation requires electronic tax returns and timely payment, with rectification allowed under specified limits. Every registered person, except specified exceptions, must electronically furnish prescribed returns of supplies, input tax credit, tax payable and tax paid for each tax period with deadlines varying by taxpayer category; the Commissioner may extend time limits by notification, tax due must be paid by the return due date, returns are required even if no supplies occurred, omissions or incorrect particulars discovered by the taxpayer (not arising from authority action) may be rectified in a subsequent return subject to interest and a statutory cutoff, and no return may be filed for a tax period while earlier period returns remain outstanding.