You can use folders to organize the apps on your Home screens. Rearrange folders—just as you do apps—by dragging them around your Home screens or to the Dock.
Create a folder: Touch an app until the Home screen icons begin to jiggle, then drag the app onto another.
iPhone creates a new folder that includes the two apps, and names the folder based on the type of apps. To enter a different name, tap the name field.
Open a folder: Tap the folder. To close a folder, tap outside the folder or press the Home button 
.
Organize with folders: While arranging apps (the icons are jiggling):
Add an app to a folder: Drag the app onto the folder.
Remove an app from a folder: Open the folder if necessary, then drag the app out.
Delete a folder: Move all apps out of the folder. The folder is automatically deleted.
Rename a folder: Tap to open the folder, then tap the name and enter a new one.
When you finish, press the Home button .