how to chang the post processing profile in a C# script unity code example

Example: how to edit postprocessing through script

using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;
 
var volume = target.GetComponent<Volume>();

if (volume.profile.TryGet<Bloom>(out var bloom))
{
    bloom.intensity.overrideState = true;
    bloom.intensity.value = 2f;
}