Let’s take a look at the subscribe button editor. To access the editor, make a new subscribe button or click on the existing one from the forms list.
Below the editor, on the left side, you can see the preview of the button. On the right side, in the details tab, you can change the button title, background color, width and height of your button.
When you are done, press Save and Get HTML. That's it! Paste the HTML code into your website and you are ready to use the subscribe form.