This is actually very easy. You can show a popup message when user submit a form. First create a popup using Elementor popup builder, that you want to show when user submits the form. we dont need to set and trigger or condition for the popup just save it. Now go to the form. Form the left panel go to “Action After Submit”. Click the field and scroll all the way down to the available options. Choose Popup.
A popup option will show up/ Choose “Open popup” from “Action”. And in popup type the name of the popup you have created and choose it. Save it.
Now if you submit the form the popup will show up.