You can add class attribute to shortcode

Great! Thank you! Can I change how the button looks? Add a different class perhaps?

there is shortcode for popup button

[wpsm_button_popup btn_text="text of button"]Content of popup[/wpsm_button_popup]

Here is the screenshot

Hi,

I would like to make the What is it? text to open up a PopUp window that will have more text in it. Could you please let me know how? I saw this in the documentation but I can't figure out how that should work. 

Thank you