Once you have created your Modal Pop-up subscription form and completed the initial setup, it's time to deal with more advanced settings, such as when you want the subscription form to be displayed.
Follow the steps below to display your form when a user exits a page:
1. Click on the Visibility Settings step located on the left side menu.
2. In the Visibility Settings step, click on the Upon Exit option. 
When you select this option, the subscription form will be displayed when someone is about to leave the page. You will need to specify the number of Seconds, Minutes, Hours, Days, Weeks or Months that need to have passed since the visitor last viewed the form.
Alternatively, you can choose to display your Modal Pop-up form when a user visits a page !