With the default wiki layout, there’s a “move” menu item hidden behind the arrow directly next to the search field (upper right corner of the page). You need to be logged in.
… and as far as I remember you also have to move the discussion page as well! (Maybe only when there is some content in there and the link to it is NOT red?)
Normal users cannot delete wiki pages. But they can use the {{Delete|…}} template on the page to let the sysops know that the page is no longer needed.
Alternatively, you might consider replacing the content of the obsolete pages with a redirect to the new page.