Recently Google started to release the "upgrade" on the ability to add emojis directly into Google Docs. Previously users had to go to Insert> Emojis and then proceed from there.
With the new update, users can use the @ symbol and type in the emoji of choice. For example when you type in @dogs, make sure to scroll down a bit as the popup menu will show you people first, and then places, etc. However, it is a short scroll and you can see many of the emojis to select from.
Embedded below is a second YouTube tutorial.