The Dock on your Mac stores all your essential apps used by your on daily basis; it is a launch pad for number of applications. In a way, Dock allows you to perform multiple actions from the desktop.
Popularity of Dock lies in its user interface, which is intuitive. Like menu bar, you can also hide and show the Dock in your Mac OS X. The system works similarly; when you hover mouse near the bottom area of screen, the Dock will appear automatically. It is easy to hide and show the Dock – either by using keyboard or by accessing OS X system preference Settings.
How to Hide & Show the Dock with Keyboard on Mac
You can hide or show the Dock in OS X automatically by pressing Command+Option+D. To gain access to the Dock, just hover mouse on the Dock area and it will reappear.
If you can't remember this shortcut on keyboard, you can hide and show the Dock from system preference; this will have similar effect.
How to Hide & Show the Dock Automatically in Mac OS X El Capitan and Earlier
You can hide and show the dock from System Preferences on your Mac; this is a one-time exercise and you don't have to remember that shortcut.
Step #1. Launch System Preferences from the Apple menu.
Step #2. Click on the Dock.
On the dialog box, you will see many options like Size, Magnification, Position of screen etc.
Step #3. Click on the check box of “Automatically hide and show the Dock”.
Post this, you can see that the Dock will automatically Hide when not in use; if you want to use apps stored on the Dock, just hover the mouse over the bottom of Mac's screen. If you are using the latest version of OS X, you don't need to perform the above actions as the Dock gets hidden automatically when you type in the command for full screen.
This feature of Mac OS X is not used by many users; they should start hiding Dock as it saves lot of space especially on MacBook Air and MacBook Pro, which have relatively smaller screen.