This question has been answered by iusemodx. See the first response.

$publickey = "xxxxxxxxxxxxxxxxxx"; $privatekey = "xxxxxxxxxxxxxxxxxx";


[!eForm? &formid=`MyForm` &to=`[(emailsender)]` &tpl=`formchunk` &report=`reportchunk` &thankyou=`thankyouchunk` &requiredClass=`required` &invalidClass=`required` &vericode=`2` &sendAsHtml=`1` &allowhtml=`0` &subject=`MySubject`!]
<div id="ctform">[+validationmessage+]
<form method="post" action="[~[*id*]~]">
<input type="hidden" name="formid" value="MyForm">
<div>
<label for="name">Name: <em class="required">*</em><br>
<input type="text" name="name" id="name" eform="Name:string:1">
</label>
<label for="email">Email Address: <em class="required">*</em><br>
<input type="text" name="email" id="email" eform="E-mail Address:email:1">
</label>
<label for="subject">Subject: <em class="required">*</em><br>
<input type="text" name="subject" id="subject" eform="Subject:string:1">
</label>
</div>
<div>
<label for="message">Message: <em class="required">*</em></label>
<textarea rows="10" cols="55" name="message" id="message" eform="Message:string:1"></textarea>
</div>
<!-- ############## -->
[+captcha_html+]
<!-- ############## -->
<input type="submit" value="Send">
</form>
</div>

If you want to cutomise the recaptcha box, making it more like your design, take a look here
