It doesn't require that you go in and change the code to specify email to send to. It's made to use the css styling and theme of your forum. It works with the permissions system of SMF.
Frankly, your request wasn't something that could be answered as it lacked a lot of the definition necessary. You gave no details as to the type of form you would want to post to a thread (form values pulled from database for dropdowns and option buttons or s couple of simple fill-in-the-blank fields). You didn't say anything about hoiw it's to be used and by whom (guest posting is different from user posting). You didn't say whether the target board and topic is or is not something the submitter would/should have access to in order to edit.