Please follow below steps to set success page redirection on form success submit.

• Open index.html and find you form code
• Apply attribute data-success-redirect=”y” on form tag with class=”form-widget”. Review example code below.

• <form action="form-data/formdata.php" class="form-widget" data-success-redirect="y">
  ....
  </form>

• Than open js file => js/rgen.js <= file and find below code.

• /*
  URL OF SUCCESS PAGE ON FORM SUBMIT
  *********************/
  success_url: "thankyou.html"

• Set you success page url on success_url variable as display in above example code
• Done now your form redirect on success page once it successfully submitted by user.