CF7 offers some JavaScript events that we can hook into. Using those events, we can create a small snippet to open a Popup after a successful contact form submission:
<script>(function ($) {
DiviArea.addAction('ready', function () {
$('.wpcf7').on('wpcf7submit', function (event) {
// Status "mail_sent" means, that the form submit is complete.
if ('mail_sent' === event.detail.status) {
DiviArea.show('#after-submit'); // ← Change this to your Popup ID.
}
});
});
})(jQuery);</script>