To edit a form, simply go to the forms section. You can either click on the edit symbol or select options and then choose edit to access the editing section.
This will take you to the editing settings where you can make your changes exactly as you did when you created your form. The overview page will let you set up change the form title and the deadline and form description.
"Questions" will allow you to make changes to your form and edit your questions:
Under Settings, there is tabs for general, email templates, score bars, application limits, and pre/post-apply pop-ups.