I am trying to use this method to display an external HTML page

I am trying to use this method to display an external html page. But when I insert the code with the iframe and press ok, the code is simply not saved and when I edit it again, nothing appears.

It's for the PDF file, not for HTML. Please use our iframe widget instead: https://widgets.jotform.com/widget/iframe_embed. When using this widget, you will need to provide the link of the HTML page only, not the entire iframe codes.