With Document/Literal encoding/ Message oriented application, the payload of a message is an XML fragment that can be validated against the corresponding XML schema, for instance:

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope
    xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"
    xmlns:mi="http://www.somedomain.com/xyz/message-id"
    xmlns:proc="http://www.somedomain.com/xyz/processed-by"
    xmlns:po="http://www.books.com/purchase">
    <soap:Header/>
    <soap:Body>
        <po:purchaseOrder orderDate="2008-09-22"
            xmlns:po="http://www.somedomain.com/xyz/PO">
            <po:accountName>Books.com</po:accountName>
            <po:accountNumber>923</po:accountNumber>
            ...
            <po:book>
                <po:title>Air Guitars In Action</po:title>
                <po:quantity>300</po:quantity>
                <po:wholesale-price>14.99</po:wholesale-price>
            </po:book>
        </po:purchaseOrder>
    </soap:Body>
</soap:Envelope>

RPC (remote procedure call)/Literal more closely corresponds to remote procedure invocations.
For instance, the method: public float getBookPrice(String inISBN) would correspond to the following RPC/Literal request message:

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope
xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:sd="http://www.somedomain.com/xyz/BookQuote">
   <soap:Body>
      <sd:getBookPrice>
          <isbn>0321146182</isbn>
      </sd:getBookPrice>
   </soap:Body>
</soap:Envelope>

One important difference between RPC and Document web services is that with RPC web services, XML schema will only be created for complex type parameters. It is thus not possible to validate the entire XML fragment contained in the SOAP body.
With Document web services, however, the XML schema needs to define the ENTIRE XML fragment contained in the SOAP body. Consequently, the entire message can be validated against the XML schema.