Facebook api how to add iframe to page?

Question

Facebook

Good day to all.
I'm just getting started with how Facebook apps work.
What to do:
My site has a manager with a Facebook account. He (the manager) created several pages on Facebook. Now he wants to be able to create an iframe in the admin panel (on my site) in a couple of clicks on the Facebook page he has chosen, in this iframe one of the pages of my site will be loaded.
What I did: I
created a facebook application, I was able to get a list of pages created by the manager.
Question:
Is it possible to create an iframe application on the page I specified through Facebook api. If so, where can I find information on this topic. And if not, what would you recommend?
I use php and Facebook SDK 4