There are two options for creating redirect pages in Sitefinity. You can create a page that points to another page and will show up in the navigation, or simply update an existing page to accept a secondary URL.
OPTION 1: Creating a redirect page
Option 2: Adding an Additional URL(s) to an existing page
This is ideal for adding web addresses from pages that may have existed on a previous website but moved and have a different address on the new website AND doesn't need to be shown in the navigation.