Open a static page/section into a modal

How do I use the iframe? do I have to put the page’s url inside it?..I was thinking that maybe it can be more practical if I can I do it with sections?..like linking the Iframe to a section of another page so it will only shows me that section.

can you give me a practical example with a read only link please.

I attached an image that explain what I’m trying to achieve.

Thank you!