Prefabs - Concept and usage - Unity Official Tutorials

Prefabs in Unity are preconfigured game objects

that you create in the scene

and store in the project.

They can then be instantiated or cloned,

meaning to create an instance of them

during the game.

They have all manner of uses and are a key part

of development in Unity.

They are used for everything from rockets

to enemies, to procedural levels.

To make a prefab simply create your game object

in it's desired configuration in your scene,

from whatever components you need,

and then drag it to the project panel

to save it as a prefab.

It can then be deleted from the scene.

To edit a prefab you can either select it in the project,

and adjust properties in the inspector.

Or drag an instance of it back in to the scene,

edit it in the inspector,

and then press the apply button at the top.

This saves changes back in to the prefab

and you can then remove the instance from the scene

yet again.

Also, if you have many instances of a prefab,

and you make edits to one of them,

and decide you would like others to be the same

you can hit apply.

The other instances will inherit this update

from the prefab's settings.

Likewise if you make a change to

one of your instances

and you decide you don't like it anymore

you can revert to the settings of the prefab

by clicking the revert button at the top.