Hey @hunesher! I’d recommend creating or finding an image that is the shape you’d like, and has a transparent background. You can upload that as a “background” image for your form in the Styles tab, set the background color to transparent, and then position the form elements on top of it. The end result will be a form with a custom shape! Here’s an example image you can use if you want to test this out! 

A tip on setting the form background transparent: use this slider in the Styles tab: 

THANK YOU SM!