Your iPhone's Home screen contains a bevy of useful apps you can tap to launch and use. This table offers a rundown of the apps you'll find on the iPhone's Home screen, a brief explanation of what each one does, and a listing of some of their integrated functions.

iPhone App Name Purpose
App Store Offers free and for-purchase applications.
Calculator Provides a four-function calculator in portrait view and a scientific calculator in landscape view.
Calendar Stores appointments and events on a calendar.
Camera Captures photos and videos.
Clock Tells time in one or more locations, sets alarms and timers, and times running or swimming laps.
Compass Provides true north and magnetic north orientation.
Contacts Stores names, phone numbers, and addresses (both physical and electronic).
FaceTime Lets you videochat with other Mac or iOS users with an iPod touch or iPad. (To FaceTime with another iPhone, first place a call with the Phone app and then tap FaceTime.)
Game Center Keeps your own game scores and compares rankings with friends.
Health Helps track your fitness activity, diet, and medical diagnostics.
iBooks Lets you purchase, download, and read e-books.
iTunes Offers free and for-purchase media — music, videos, TV shows, audiobooks, and ringtones.
iTunes U Helps you browse the course catalog, enroll, and attend class.
Mail Sends, receives, and manages email.
Maps Finds and shares locations and directions.
Messages Sends, receives, and manages SMS, MMS, and iMessage text messages.
Music Lets you listen to and manage audio media.
Newsstand Keeps periodical subscriptions in one place.
Nike + iPod Records and monitors walking and running workouts.
Notes Provides a portable, electronic yellow notepad for taking and sharing notes.
Passbook Manages your store cards and boarding passes.
Phone Makes voice and FaceTime phone calls, lets you initiate and receive conference calls, manages voicemail, and enables you to access Contacts.
Photos Stores and displays photos you've taken and videos you've recorded.
Podcasts Enables you to find, manage, listen to, and watch podcasts on a variety of topics.
Reminders Lets you jot down things you need to remember and get reminders for them.
Settings Adjusts settings and preferences for iPhone and apps.
Stocks Tracks market movements and individual investments.
Tips Gives you suggested tricks and tips from Apple.
Videos Lets you watch videos.
Voice Memos Records audio.
Weather Provides up-to-date, worldwide weather forecasts.

Download the following apps for free from the App Store.

iPhone App Name Purpose
Find My Friends Locates your iOS-toting friends.
Find My iPhone Helps someone you know find his iPhone, iPad, or Mac.

A few functions are integrated into many of the iPhone apps:

Function Purpose
Facebook If you install the Facebook app, Facebook appears on the Share Sheet so you can post status updates and photos from apps such as Photos and Safari.
Print Prints messages, web pages, photos, and more to an AirPrint-enabled printer.
Share Sends photos, video, voice memos, maps, contacts, web links, and notes via AirDrop, email, text messages, iMessage, Facebook, and Twitter, as well as prints, copies, and opens documents in a compatible app. All commands are found when you tap the Share button to open the Share Sheet.
Siri Gives vocal commands to perform iPhone tasks such as getting directions, writing and sending email, searching for a movie time or game score, and finding out the weather forecast (iPhone 4S or later).
Twitter If you install the Twitter app, Twitter appears on the Share Sheet so you can send tweets from within apps like Maps, Photos, and Safari.
Voice Control Use vocal commands to perform simple tasks such as audio playback, making phone calls, and asking for the time (works when Siri is turned off on iPhone 4S or later or as part of Siri when Siri is on).