Short answer
At minimum: a commercial invoice with HS codes and fibre content, a packing list, and the air waybill or bill of lading. A certificate of origin may be needed for reduced duty under a trade agreement.
The exporter should hold an Import Export Code (IEC). If your supplier does not export directly, a Surat freight forwarder or sourcing agent can act as exporter and prepare documents. Keep copies of everything; customs authorities may ask for them after the goods arrive.
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