The Dock on your Mac
The Dock, at the bottom of the screen, is a convenient place to keep the apps and documents you use frequently.
Open an app or file. Click an app icon in the Dock, or click the Launchpad icon 
in the Dock to see all the apps on your Mac, then click the app you want. You can also search for an app using Spotlight 
, then open the app directly from your Spotlight search results. Recently opened apps appear in the center section of the Dock.
Add an item to the Dock. Drag the item and drop it where you want it. Place apps in the left section of the Dock, and files or folders in the right section.
Remove an item from the Dock. Drag it out of the Dock. The item isn’t removed from your iMac—just from the Dock.
See everything that’s open on your Mac. Click the Mission Control icon 
in the Dock, or press 
on your keyboard to view your open windows, desktop spaces, full-screen apps, and more, making it easy to switch between them. See Use Mission Control on your Mac.
Tip: Click Dock in System Preferences to make the Dock larger or smaller, add or remove items, move it to the left or right side of the screen, and even set it to hide when you’re not using it.
Learn more. See the Apple Support article Use the Dock on Mac.