<apex:page renderAs="pdf" standardController="Contract">
    <apex:detail relatedList="true" title="true"/>
    <div style='clear:right;margin-top:50px'>
        <div style='float:right'>____________________________________</div>
        <div style='float:right'>By:</div>
    </div>
    <div style='clear:right;margin-top:50px'>
        <div style='float:right'>____________________________________</div>
        <div style='float:right'>Date Signed:</div>
    </div>
</apex:page>

public with sharing class SendToDocuSignController {
    private final Contract contract;

    public String envelopeId {get;set;}
    private String accountId = '';
    private String userId = '';
    private String password = '';
    private String integratorsKey = '';
    private String webServiceUrl
        = 'https://demo.docusign.net/api/3.0/dsapi.asmx';

    public SendToDocuSignController(ApexPages.StandardController controller)
    {
        this.contract = [select Id, CustomerSignedId, AccountId, ContractNumber
            from Contract where id = :controller.getRecord().Id];
        envelopeId = 'Not sent yet';

        SendNow();
    }

    public void SendNow()
    {
        DocuSignAPI.APIServiceSoap dsApiSend
            = new DocuSignAPI.APIServiceSoap();
        dsApiSend.endpoint_x = webServiceUrl;

        //Set Authentication
        String auth = '<DocuSignCredentials><Username>'+ userId
            +'</Username><Password>' + password
            + '</Password><IntegratorKey>' + integratorsKey
            + '</IntegratorKey></DocuSignCredentials>';
        System.debug('Setting authentication to: ' + auth);

        dsApiSend.inputHttpHeaders_x = new Map<String, String>();
        dsApiSend.inputHttpHeaders_x.put('X-DocuSign-Authentication',
            auth);

        DocuSignAPI.Envelope envelope = new DocuSignAPI.Envelope();
        envelope.Subject = 'Please Sign this Contract: '
            + contract.ContractNumber;
        envelope.EmailBlurb = 'This is my new eSignature service,'+
            ' it allows me to get your signoff without having to fax, ' +
             'scan, retype, refile and wait forever';
        envelope.AccountId  = accountId;


        // Render the contract
        System.debug('Rendering the contract');
        PageReference pageRef = new PageReference('/apex/RenderContract');
        pageRef.getParameters().put('id',contract.Id);
        Blob pdfBlob = pageRef.getContent();

        // Document
        DocuSignAPI.Document document = new DocuSignAPI.Document();
        document.ID = 1;
        document.pdfBytes = EncodingUtil.base64Encode(pdfBlob);
        document.Name = 'Contract';
        document.FileExtension = 'pdf';
        envelope.Documents = new DocuSignAPI.ArrayOfDocument();
        envelope.Documents.Document = new DocuSignAPI.Document[1];
        envelope.Documents.Document[0] = document;

        // Recipient
        System.debug('getting the contact');
        Contact contact = [SELECT email, FirstName, LastName
            from Contact where id = :contract.CustomerSignedId];

        DocuSignAPI.Recipient recipient = new DocuSignAPI.Recipient();
        recipient.ID = 1;
        recipient.Type_x = 'Signer';
        recipient.RoutingOrder = 1;
        recipient.Email = contact.Email;
        recipient.UserName = contact.FirstName + ' ' + contact.LastName;

        // This setting seems required or you see the error:
        // "The string '' is not a valid Boolean value.
        // at System.Xml.XmlConvert.ToBoolean(String s)"
        recipient.RequireIDLookup = false;

        envelope.Recipients = new DocuSignAPI.ArrayOfRecipient();
        envelope.Recipients.Recipient = new DocuSignAPI.Recipient[1];
        envelope.Recipients.Recipient[0] = recipient;

        // Tab
        DocuSignAPI.Tab tab1 = new DocuSignAPI.Tab();
        tab1.Type_x = 'SignHere';
        tab1.RecipientID = 1;
        tab1.DocumentID = 1;
        tab1.AnchorTabItem = new DocuSignAPI.AnchorTab();
        tab1.AnchorTabItem.AnchorTabString = 'By:';


        DocuSignAPI.Tab tab2 = new DocuSignAPI.Tab();
        tab2.Type_x = 'DateSigned';
        tab2.RecipientID = 1;
        tab2.DocumentID = 1;
        tab2.AnchorTabItem = new DocuSignAPI.AnchorTab();
        tab2.AnchorTabItem.AnchorTabString = 'Date Signed:';

        envelope.Tabs = new DocuSignAPI.ArrayOfTab();
        envelope.Tabs.Tab = new DocuSignAPI.Tab[2];
        envelope.Tabs.Tab[0] = tab1;
        envelope.Tabs.Tab[1] = tab2;

        System.debug('Calling the API');
        try {
            DocuSignAPI.EnvelopeStatus es
                = dsApiSend.CreateAndSendEnvelope(envelope);
            envelopeId = es.EnvelopeID;
        } catch ( CalloutException e) {
            System.debug('Exception - ' + e );
            envelopeId = 'Exception - ' + e;
        }
    }
}

<apex:page standardcontroller="Contract" extensions="SendToDocuSignController">
    <h1>Your eSignature request is being sent to DocuSign API!</h1>
    <hr/>
    <apex:form >
        <apex:commandButton value="Send Again!" action="{!SendNow}"/>
    </apex:form>
    <hr/>
    <strong>The DocuSign EnvelopeId:</strong>{!envelopeId}<br/>
</apex:page>

/apex/SendToDocuSign?id={!Contract.Id}

var SourceID = "{!opp.Id}";
var LA = "0";
var DST = "XXXXX"; //This is the template id that you will only get from docusign portal
var OCO = "Send"; //this specify that the page is automatically send to avoid clicking send from that VF Page
window.open("/apex/dsfs__DocuSign_CreateEnvelope?DSEID=0&SourceID={!opp.Id}&LA=0"+"&DST="+DST+"&OCO="+OCO, '_top');