If you want to find a Plus Code for a certain location, it is not that easy. At this point, you can't do it on Google Maps. When you left-click on an area and choose What's here?, it will give you latitude and longitude but Maps does not give you the Plus Code.
However, what you can do is, you can go to plus.codes and use the Find your code option.
Zoom in or out until the area that you want fills the screen. A Plus Code designates an area in the shape of a rectangle. It's not a point like latitude and longitude. You can take advantage of that by zooming in and out until you get to the size of an area that you want. After you have the right area, go to the menu and choose the option to see the Grid.
After choosing the option to show the grid, you will see the rectangles that are available to you. In this case, the area labeled 86FVCF fits Hocking Hills State Park which is the area that I am looking for. 86FVCF is the first part of the full Plus Code that you will see later in this article.
There is also a shortened code available at the bottom of the screen. CFG7+JP, works for anyone that lives close to the park. It's a shortened, partial version of the code. CFG7+JP does not contain the beginning 86FV portion of the 86FVCF code, so it works when you are already relatively close to the area.
On the left side of the plus.codes screen, you will see the full Plus Code and the shortened Plus Code that can be used for local navigation. If you want the entire Plus Code, which is probably the best practice if you are copy/pasting, go to the left of the screen and copy it. This is your full Plus Code. It's not case-sensitive, but since we're copy and pasting it in, it doesn't matter.
Go back to your mapping program, which is Google Maps in this case, and enter this Open Location Code into the search bar. Google Maps will go to the area that corresponds to the Plus Code and drop a pin in the middle of it. Maps shows you the latitude and longitude of the center of the Plus Code but it will not show the grid with the codes on it.
Now you know how to find your Plus Code using plus.codes with the grid feature turned on and you can take that Plus Code and enter it into Google Maps, you know how to find and use a Plus Code. I hope that was helpful!