The premium version of the plugin allows you to add multiple different customized popups. You can add different forms for different popups.
Go to the site admin > CF7 Popup > Add New. Here you can select a form and change the other settings. After you are done with the customization, save it by pressing the publish button.
After that you can either use the generated short-code or set an action hook for showing the popup button.
For more details, you can check ShortCode Showing and Action Hook Showing documentation.