From the XCode docs.
A Copy Files build phase allows you to copy files and resources of any type to specific locations as part of the build process. It complements the build phases that copy specific types of files. An example is the Copy Headers build phase, which deals only with header files. You can have as many Copy Files build phases as you need in a target.
For example, using a Copy Files build phase, you can copy fonts to/Library/Fonts. Or, if you’re developing a plug-in, a Copy Files build phase can copy the generated plug-in to the appropriate location. You can have as many Copy Files build phases in a target as you need.
To create a Copy Files build phase:
In the project window, open the target to which you want to add the build phase, and select the build phase after which to add the new build phase.
Choose Project > New Build Phase > New Copy Files Build Phase. Xcode adds the new Copy Files build phase after the build phase selected in the Groups & Files list.
Drag the files you want to copy from the Groups & Files list to the Copy Files build phase.
To configure the new Copy Files build phase, select it and open the Copy Files build phase editor, shown in Figure 2-5.