My website has a Facebook page that I don't have admin access for from my Facebook account. It must have been created for me by somebody else.
How do I request access to this page from Facebook. I can prove that the page is for me and my website.
Yes, But users who created pages will only be able to add other admins to their pages via admin rules option from the fb page.
You can add yourselves to your page by requesting the page creator, page admin to add you via "admin rules" option from edit page option fro the page.
The one whom you mentioned as "somebody" should have permission to add users as admin..
Go now ask him to add your email address which gives you permission as admin.