How can i add a folder to an existing page

How do I add a folder to an existing page on my web site

Which template are you using? Depending on that, you might have the option of an Index instead of a Folder. But a general way to add a folder is:Pages-->the '+'---> Scroll in the pop up to the bottom where it says 'other'.Generally folders contain pages, not pages contain folders, so that might be your problem.