Contact Form Builder module is the easiest way to design and generate the dynamic form, you can select/drop as many fields along with the options for the controls as per your requirements and end users can post the details to submit the details to the configured email address.
The "Simple Contact Us" module provides a fully customized Contact Us form that can be use on your website. It can be configured to use CAPTCHA or reCAPTCHA for security. The module allows the website users to send messages through the website to a given configured mailing list.
DnnDeveloper's Contact Us module is a simple module to implement a contact us page along with google map. It can easily integrate into the DotNetNuke portal and can be configured to match the layout/Skin.