What is Power Pages?
Power Apps portals and Dynamics 365 portals are now referred to as Power Pages.
There is no migration or upgrade process. You can use the new Power Pages design studio to edit sites created in Power Apps. Existing tools such as the Portals Management app and Power Platform CLI will continue to work with Power Pages.
We are currently migrating and merging the Power Apps portals documentation with Power Pages documentation. You may continue to see some Power Pages features referred to as Power Apps portals during this transition.