Metadata Create Custom Field

Sample SOAP Request Message - Create a Custom Field

<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
 <soapenv:Header>
  <ns1:SessionHeader soapenv:mustUnderstand="0" xmlns:ns1="http://soap.sforce.com/2006/04/metadata">
   <ns1:sessionId>3e8700Dx00000007S3idfjhteyi!OU9bZp_SLD4NPI4VuaUlMq6ww_e6Ta52FxRp3Beu9tAPeodWKW_bDgWUGl_L8KaM9e451WY4HwutyhfsgetyxF7pqU6iDUQTWGJBoRRjKJogCW</ns1:sessionId>
  </ns1:SessionHeader>
 </soapenv:Header>
 <soapenv:Body>
  <create xmlns="http://soap.sforce.com/2006/04/metadata">
   <metadata xsi:type="ns2:CustomField" xmlns:ns2="http://soap.sforce.com/2006/04/metadata">
    <fullName>sampleco__c.samplecf__c</fullName>
    <label>samplecf</label>
    <length>100</length>
    <type>Text</type>
   </metadata>
  </create>
 </soapenv:Body>
</soapenv:Envelope>

Sample SOAP Response Message

<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns="http://soap.sforce.com/2006/04/metadata">
  <soapenv:Body>
    <createResponse>
      <result>
        <done>false</done>
        <id>04sx00000000Do4AAE</id>
        <secondsToWait>2</secondsToWait>
        <state>InProgress</state>
      </result>
    </createResponse>
  </soapenv:Body>
</soapenv:Envelope>