The power of the HTML5 inside Construct 3. Create HTMLElements, handle events and manage CSS style.
It depends on what you mean by inserting an html page. You can use the "Text like HTML" option and insert an HTML code into the text:
```html
<p>This is a paragraph.</p>
<p style="color:red">This is another paragraph.</p>
<h1>HELLO!</h1>
<img src="https://construct-static.com/images/v865/r/global/construct-3-logo_v43.png" alt="c3logo">
```
This way you can create an html component on top of the construct canvas.
I don't think you can bypass an iframe to display an external page.