Once you edited the appearance of your popup and you are happy with it, you can convert the current design into a custom template. When you create a custom template you could easily duplicate your design across other popups or sites with just a few clicks.
To export the template go to WP Popups -> tools -> Export and choose the desired popup of which you want to extract the template.
Once you do that you will get some auto-generated PHP code with all the template settings.
With the generated code you could do a couple of things. The easier is just to paste that code in your Theme’s functions.php file and your template will be available for use.
A more advanced way could be to generate a plugin file that can be easily uploaded into your sites. For that create a file called wppopups-custom-templates.php with the following code on top:
/** * Plugin Name: WP Popups Custom templates * Plugin URI: https://wppopups.com * Description: My set of custom templates for WP Popups * Author: Your Name * Author URI: https://wppopups.com * Version: 1.0.0 */
Then simply paste all your template codes in that file and install it as a regular plugin by uploading it in wp-admin -> Plugins -> Add New