Select the time in the bottom-right corner of the screen.
Select the Settings gear in the pop-up window to open your Chromebook Settings.
Scroll down to the bottom of the settings page and select Advanced.
Scroll down the page again and select Languages and Input.
Again, scroll down the page and select the toggle switch next to Show input options on the shelf to enable it.
Close the settings and select US in the shelf to bring up the input options.
Tap or click the symbols in the bottom row to browse the different categories, then select the keyboard icon in the bottom-right corner to minimize the emoji keyboard when you're done.