Yes, you can. Before you paste the code onto your Joomla article, you need to make certain settings for your Joomla website, in order to allow the JavaScript code of our forms run. To enable these settings, just follow the steps below.

1. Access the Site menu → Global Configuration → Text Filters and for Super Users make sure the No Filtering option is enabled.
2. In the Extensions tab go to Plugin Manager → Editor TinyMCE → Basic Options → New Lines: Br Elements → Prohibited Elements. Make sure you remove Script and iFrame from that list.
3. While still in Extensions, access Template Manager → Templates and choose your active template. Hit Edit main page template.
4. Next to $doc → addStyleSheet, insert this line:
   addStyleSheet(‘http://www.123contactform.com/includes/tinybox/tinyboxstyle.css’)
   (Optional: if you don’t have $doc = JFactory::getDocument(); declared already, add it before $doc->addStyleSheet).
5. Now go to the article you want to insert forms to. In Edit Article click Toggle Editor.
6. In your 123ContactForm dashboard, access the form menu, Get Code and Publish > Lightbox. Choose the option you need (text link, image or floating button), then copy the form code and paste it into the Joomla article editor.