How to insert individual header codes?

So I need to test a few Open Graph codes to insert in individual pages.

Ideally I want to have a “feature image” WITHOUT the image actually showing up on the page.

I would need to have access to the header of each page and insert different codes for each page to make it work properly.

Is there a plugin that would allow me to insert codes on the headers of individual pages?

The page I need help with: [log in to see the link]