Magento has a built-in contact form that does the job, but isn't the easiest to edit. You may for example want to add your company address, contact details or even a Google Map.
This can be quite easily achieved by creating your own CMS page and including / embedding the contact form portion of the standard Magento contact form as a static block.
To achieve this, do the following:
1. Create your CMS page in Magento Admin (CMS > Pages)
2. Paste the following code in your HTML where you would like the contact form to be positioned in your CMS page:
<!-- contact form start –->
{{block type="core/template" name="contactForm" form_action="/contacts/index/post" template="contacts/form.phtml"}}
<!-- contact form end -->
If you need to edit the actual contact form HTML (more advanced), edit the file at:app/design/frontend/default/[yourtheme]/template/contacts/form.phtml
. Your theme location may differ.