Let me show you how to customize the sign-in and registration page in Power App Portals.
There is no obvious way to customize the sign-in and registration page in Power App Portals. The pages don’t exist in the Web Pages directory, and there is no Web Template. Even if you are logged into the portal as an administrator the Portal Content Editor Toolbar doesn’t appear on these pages. There is no way – essentially – to edit the look and feel of these pages.