Export under LUT enables zero-rated supplies without IGST, subject to time-bound export/payment requirements and recovery on default. Exporters may supply goods or services without payment of integrated tax by furnishing a Letter of Undertaking (LUT) or bond in FORM GST RFD-11 before export; failure to export or realize payment within prescribed periods requires payment of tax with interest and leads to withdrawal of the LUT/bond facility until tax is paid, with restoration upon payment. LUTs are valid for the financial year, accepted upon online ARN acknowledgement without physical documents, while bonds and bank guarantees apply to ineligible persons and running bonds must cover self-assessed export tax liabilities.