This is a basic Filter app show casing some of what the Unity Learn AR Face Filter does. https://learn.unity.com/course/create-with-ar-face-filters.

This is done using C# instead of the visual scripting which unity does. This will be available to learn how to build using unity and c# available at, https://www.youtube.com/watch?v=yvlPlJvSBQ4&list=PLptTfKPKcF0EIBMu6jzJOt8O4JfBeOb_d