We would like users to be able to submit changes to a page that could then be reviewed by an admin before posting live. Is there a way to set that up?

[Nic Brough -Adaptavist-]

Not natively - Confluence is a Wiki, it is built for rapid editing and immediate publication of change.

Of course, there's a lot of perfectly good reasons for controlling the publication, and, as you'd expect, you have addon options.  Take a look in the marketplace for Comala Workflows and Scroll Versions - they both do this sort of thing, albeit in very different ways.