If you want to show a Popup Globally on your site then you must follow this guide. We'll see how to show the Popup you've created Globally on your site. It could be a Sale Notice Popup, Important Notice or anything. We can use the Divi's Theme Builder to show the Popup globally. Just Edit your Global Header or Footer as both shows on your whole site so will the Popup. Let's Edit the Global Footer. Once you've opened the Module settings, you can go to Advanced tab -> Visibility -> Use Popup and set up the Popup the way you like. Hope you'll found it useful, Let us know If you need any help. Have a great day!