Welcome to the Anvil Forum, @lisajwright21.
By default, every Anvil app is a “single-page web app”. That is, there is only one URL for the entire app. When the app, running inside the browser, changes to a new Form, it literally re-writes the in-browser page on-the-fly, entirely inside the browser. This does not change the page’s URL.
If you want your app’s pages to have individual URLs, you may want to look at this post:
Routing, navigation with URL Hash
The authors have set up a framework that simulates distinct URLs, within the Anvil app, and lets them be used as if they were “real”, traditional URLs.