Package Manager:

The Package Manager in Unity is a built-in tool that allows developers to easily discover, install, and manage packages or extensions for their Unity projects. These packages can include new features, tools, assets, and services that enhance the functionality and capabilities of Unity.

What is URP?

URP is a rendering system in Unity that helps make your game or application look good on different devices like phones, tablets, computers, and game consoles. It's like a set of tools and rules that tell Unity how to draw and show things on the screen.

How Does it Work?

Optimization: URP helps make your game run faster by using tricks to make things like lighting and shadows look good without using too much processing power.

Customization: With URP, you can change how things look in your game by adjusting settings like colors, lighting, and special effects. It's like using a magic paintbrush to change the colors of your painting.

2D Support: URP also helps with making 2D games. It has tools that are specifically designed to help draw and animate 2D characters and objects.

Easy to Learn: Even though it might sound complicated, URP is designed to be easy to learn. There are lots of tutorials and guides available to help you get started.

Adding Post-Processing Volume in URP:

Add Post-Processing Volume:

In the Hierarchy window, right-click and choose
3D Object > Empty to create an empty GameObject.

Add a Post-Process Volume component to the empty GameObject
(Component > Rendering > Universal Render Pipeline > Post-Process Volume).

Assign Post-Processing Profile:

With the GameObject containing the Post-Process Volume selected, you'll see a "Profile" field in the Inspector. Drag and drop your Post-Processing Profile asset into this field to assign it to the Post-Process Volume or click on new to create new profile.

Adjust Volume Settings:

You can adjust the size, shape, and blending properties of the Post-Process Volume to control where and how the post-processing effects are applied. For example, you can adjust the "Is Global" checkbox to apply effects globally to the entire scene or uncheck it to limit effects to a specific area.

Fine-Tune Post-Processing Effects:

Play around with the settings in the Post-Processing Profile to fine-tune the look of your scene.

You can enable/disable effects, adjust their intensity, and customize parameters to achieve the desired visual style.

This is the official document from unity it contains everything you need to know about the URP and post processing: URP documentation