The “Home” button on an iPhone is the only physical button you can actually press on the front of the device. Typically the “Home” button will return you to the main menu, but this is dependent entirely on the settings you have specified for it. If your “Home” button isn’t functioning properly or to your liking, you can quickly correct this using the device’s “Settings” application. You don’t have to connect your iPhone to iTunes to accomplish the task.
Turn on your iPhone.
Tap on the function you'd like your "Home" button to perform.
You can have it return you to the first page of your menu, bring up your "Search" function, or start the device's "iPod" capabilities.
Once you've made your selection, tap the "Home" button to confirm it. You will now have fixed your iPhone "Home" button.