Hi team quick question if i have an order with backorderd qty i want to prevent the fulfillment what will be the setting in NS

Do you mean fulfilling manually in NetSuite, or via a WMS like RF-Smart.

@Tim Chapman from Celigo i have an order with 5 qty available but 1 is backordered i want that to throw the error which means even in NS manually it will not show fulfull button because it has backorderd qty

There's a field on the line items called "Commit". Change that to the "Complete Qty" option and it will only commit stock when all of it is available which will then make it fulfillable.