Sprite sheet with Unity

The goal here is to use sprite sheet with Unity.
The most common scenarios are:

Import sprite sheets

Importing sprite sheet with Unity is simple, just drag and drop the sprite sheets in the resource folder.
If you need a sprite sheet you can test with this one : sonic-sprite-sheet.png

Next make sure the Sprite mode is set to Multiple :

Sprite sheet Mode

Then you can open the Sprite Editor :

Sprite sheet Editor

You can slice the sprites, normally you do not need to tchange the default options :

Sprite sheet Editor Slice Menu

After the sprite sheet slicing, you can click on Apply to confirm the change or Revert.

Slice Sprite Editor

After the slicing you should have :

After the slicing

In the resource folder you see the sprites :

After slicing in the resource folder

Everything is done, you can now use the sprites in your game!

Reduce the number of draws calls: Sprite Atlas

If you want to reduce the number of draws calls but you have multiple sprites in your games, you can generate a sprite sheet with unity, those are call Sprite Atlas.

To create a Sprite Atlas you can do it in less than 1 minutes : Right click on you resource folder

Create a Sprite Atlas

Then you can add the sprite you want to pack in the Inspector:

Add images to you Sprite Atlas

You can render you Sprite Atlas with the button Pack Preview.
Unity should be able to use your Sprite Atlas you do not need to do anything else.