We need to use below SOAP Webservice to apply Hold on Sales Order in Oracle Fusion:

1. Applying Hold on Sales Order:
   

WSDL URL:

Operations: RequestHold

Sample Payload:

<?xml version="1.0" encoding="UTF-8"?> 
  <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:dood="http://xmlns.oracle.com/apps/scm/doo/decomposition/orderDetailServices/DooDecompOrderDetailSvcComposite">
     <soapenv:Header />
     <soapenv:Body>
        <dood:RequestHoldProcessRequest>
           <dood:ApplyHoldRequestParams>
              <dood:SourceOrderSystem>OPS</dood:SourceOrderSystem>
              <dood:SourceHoldCode>XX_TEST_HOLD</dood:SourceHoldCode>
              <dood:HoldComments>XX Test Hold Comment</dood:HoldComments>
              <dood:SourceOrderNumber>XX_TEST_SALES_ORDER_01</dood:SourceOrderNumber>
              <dood:HoldName>XX Test Hold</dood:HoldName>
              <dood:AppliedBy>Test_user</dood:AppliedBy>
           </dood:ApplyHoldRequestParams>
        </dood:RequestHoldProcessRequest>
     </soapenv:Body>
</soapenv:Envelope>

2. Releasing Hold on Sales Order

WSDL URL:

Operations: RequestHold

Sample Payload:

<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:dood="http://xmlns.oracle.com/apps/scm/doo/decomposition/orderDetailServices/DooDecompOrderDetailSvcComposite">
   <soapenv:Header />
   <soapenv:Body>
      <dood:ReleaseHoldProcessRequest>
         <dood:ReleaseHoldRequestParams>
            <dood:SourceOrderSystem>OPS</dood:SourceOrderSystem>
            <dood:SourceOrderNumber>XX_TEST_SALES_ORDER_01</dood:SourceOrderNumber>
            <dood:SourceHoldCode>XX_TEST_HOLD</dood:SourceHoldCode>
            <dood:HoldReleaseReasonCode>XX_TEST_RELEASE_CODE</dood:HoldReleaseReasonCode>
            <dood:HoldReleaseComments>Release Hold on Sales Order</dood:HoldReleaseComments>
         </dood:ReleaseHoldRequestParams>
      </dood:ReleaseHoldProcessRequest>
   </soapenv:Body>
</soapenv:Envelope>