FedEx - Tin Number

functions.php

add_filter('wf_fedex_request','wf_fedex_tin_number', 10, 2 );
    function wf_fedex_tin_number($request,$order){	
		$tintype = "BUSINESS_STATE";
		$tin_number ="123456"; //replace tin number here
		
		if(!empty($tin_number)){
			$request['RequestedShipment']['Shipper']['Tins'] =  array(
				'TinType' => $tintype,
				'Number' => $tin_number
			);
		}
        return $request;
    }