First you login **Magento admin ->  CMS -> Pages**

Select your page and input your HTML code as you normally would on any other information you include the page, then select **Content** tab and add it. 

The below lines to add your **cms -> page**:

    {{block type=”core/template” name=”contactForm” form_action=”{{store direct_url=”contacts”}}/index/post” template=”contacts/form.phtml”}}