How to pop up a form just before people leave the website

Another question : I want to put a  POP UP FOR on my website but I would  the pop up appear just before people leave the website . Have you an idea ?

You can embed a form as a lightbox popup into your website by following this guide:

https://www.jotform.com/help/220-How-to-create-a-lightbox-form

You can have this form automatically pop up when your users navigate to your site, or with a delay, by following this guide:

https://www.jotform.com/help/203-How-to-Auto-popup-a-Lightbox-Form

When it comes to popping out our form when users are trying to leave your website, I'm afraid that this is not supported, as explained by the JotForm's founder in the following support thread:

https://www.jotform.com/answers/151911-Is-it-possible-to-get-it-to-open-on-exit

We do not currently support having forms pop up to users when they are trying to leave your website.