New scenes in URP do not use post-processing by default. Instead you must manually add post-processing to any new scene which you create. You can then configure each effect individually to create the visual effect you want.
Note: Some examples and scene templates in URP use post-processing by default. If you use these to create a new scene, you might not need to make any changes.
To add post-processing to a scene:
Now you can use the Volume Override to enable and adjust the settings for the post-processing effect.
Note: Post-processing effects from a volume apply to a camera only if a value in the Volume Mask property of the camera contains the layer that the volume belongs to.
Each post-processing effect in URP has individual settings you can adjust to tune the visual impact they have on your scene. For more information on the post-processing effect settings, refer to the reference pages in the Effect List.