What plugin add a page


Well-known member
That's a custom developed site, it has nothing to do with XenForo what so ever.

You can add custom pages in XenForo but you have to type in HTML, it's not facilitated in a way that regular end-users can use, nor is there currently an addon that does this (well).

That said, even if there was, you could not simply make a page like the one you showed here without having web dev skills.