In this image I am going to demonstrate how to use the Pathfinder panel in Adobe Illustrator. The panel that I used unfortunately cannot be seen in the screenshots that I am posting currently. But, I can show you where to go on the document in the image below.
Where it is circled in red says Window, once you click on Windows it shows a list that has many different options. One of those options near the end is called Pathfinder, click on it and it opens a little grey rectangular box with three different options
We are going to focus on the Pathfinder option, click on pathfinder then click on the two boxes that are in white and are overlapping each other that I circled in red. Once you have clicked on the two squares and selected the object that you want to change the result should look like in the image below.
Notice on how all the inner lines are gone and the object has become a whole shape, this is the result of the Pathfinder Panel.
These are the different tools found in the Pathfinder Panel. In this first image with the leaves is where I will show you how to use the first three tools that I circled in red.
The first tool is called Divide, what divide will do is that it will divide any overlapping areas into their own independent shapes. The result of this is the first set of leaves that are overlapping each other with lines.
The second tool is called Trim, which is the middle leaves in the illustration above. This gets rid of the overlapping lines and stroke but it still makes them all independent shapes.
The third tool is called Merge, it’s much like Trim, but It will group any content that is the same color into one shape. The example for this is the illustration with the two blue leaves.
These are the last three tools for path finder. The first one in the red circle is the Crop tool, to use this tool I recommend that you also use the shape tool for the best results. Here I used the rectangle shape for this set of leaves. I sized up the rectangle to what I want then I chose no fill or none so the inside is transparent. Then, I sized it up in front of the leaves, clicked on Crop and the leaves were croped.
Next is Outline, Outline is going to divide the leaves but, it will do that by the stroke of the leaves. Finally, the last one is Minus Back. What this will do is that it will remove what is behind the front shape.