Documents and details for imported goods to send back.

Hi Good Day,

  Let me know the procudure for the goods procurred from other country, due to the quality defect, we are sending back to the vendor within the aggreated waranty or with out warranty, just i want to know to return the goods back to the customer,. 

What are the Documents required to send the goods to the vendor?

Is theare any Delcaration needs to be furnished ? is so please suggest.

Please help on this.