Keep the content of your portal concise and relevant by removing obsolete pages. By disabling an existing landing page, you ensure that users cannot add it to their menus.A page that you remove from an application is no longer available in the Landing pages list.
For applications without Cosmos React UI, see Creating and managing pages for applications.
Open your portal:
In the navigation pane of App Studio, click Channels.
In the Current channel interfaces section, click the icon that represents the portal from which you want to remove a custom page.
On the portal page, on the Content tab, click the Landing pages category.
In the Landing pages pane on the left side of the screen, locate the page that you want to delete.
Hover over the page name, and then click the More icon.
Click Remove page.