After doing this, the dock will disappear, allowing you to use that space for whatever you’re working on. When you want to use the Dock, simply move your mouse pointer to the screen space where it used to be and it will appear.
You can get a little more space by hiding the menu bar as well. Within System Settings, go to control center settings, and then set the Automatically hide and show the menu bar option of Always.
This will hide the menu bar at the top of the screen in the same way you hid the dock before. Now, obviously this gives you less space than hiding the base, and some people won’t love not having a clock on the screen at all times. But there is a little more space and I find that not seeing all the menu bar icons makes it a little easier to concentrate.
Do you need even more space? If you have an iPad you can use it as a second monitor for your Mac, as I explained here. Basically, if your iPad is nearby, you can head to Screens Under System Settings, click the + and add your iPad as a screen. I really like to use it when I’m traveling; It gives me a little extra space to work when I’m away from my desk and my external monitor.