Custom enables you to apply a material to customize your own post process effect.
Add a Custom Object
Go to the Hierarchy panel and click the Add button [+] > Post Effect > Custom.
A Camera component and Post Process component are automatically added in the Inspector panel.
The Custom object is automatically added to the Post Effects render group in the Hierarchy panel. Learn more about render groups.
Use the Material property to apply a customized post process effect.
Create a Pixelated Effect
Once you’ve added a Custom post process effect, you can create a customized, pixelated effect.
Open the Asset Library, go to Screen Effects, and click the Pixelate effect. Click Import to access the material in the Assets panel.
Click the Custom post effects in the Hierarchy panel and locate the Custom component in the Inspector panel. Click the Material field, select Pixelate_Mat, and click OK.