You must include 3 extra fields in the Form Layout for Authorize.net to work.
Field Name
Example
Notes
Card Number
<input id="s_e_card_num" class="required" type="text" />
Card Expiry
<input id="s_e_card_exp" class="required" type="text" placeholder="MM-YYYY" />
The data format must follow that in the placeholder in our example
Card CVV
<input id="s_e_card_cvv" class="required" type="text" />