youtube image
From YouTube: Getting started with building custom app pages for SharePoint Online using SharePoint Framework

Description

This video demonstrates in practice how to get started with the app pages in SharePoint Online by using SharePoint Framework 1.8 or newer version.

Any web part can be exposed as an app page by adjusting the web part manifest settings. App pages are then shown as an option in the page layout picker. They can be also programmatically deployed if needed.

More details on the app pages in SharePoint Online is available from the following article: https://docs.microsoft.com/en-us/sharepoint/dev/spfx/web-parts/single-part-app-pages