Use site to define the default styling and navigation to get the look and feel of your solutions to your requirements.
You can use the same forms in different contexts to get different look and feel. You can create, modify and delete a site, and specify the supported language to use for your site.
Within the same site, you can configure settings to use for your Desktop, Tablet, and Phone forms. This means that you could have different styling for the same form depending on the settings, and the device on which you are viewing the form. For example, if the form is being viewed on a desktop, the form will be displayed based on the desktop settings (unless a specific header form or navigation has been selected in the form).
The same form can be used in multiple sites, but the look and feel changes based on the theme, header and menus associated with the site.
See Create a site.