What is an app, and how does it work? App is short for application, which is a software program. Apps can help people play games, read the news or find their way. You probably use some of them every day, but few people stop to ask what happens inside. It is a good question to ask, because the answer is full of surprises. Let's open the box and look at the parts, one step at a time, and see how the whole thing fits together. Here we go, and take your time. Ready? Here we go.

Every phone has hardware, which is the equipment, and software, which is the programs the equipment runs. One program is the operating system. An operating system is the main software that manages a computer's resources and lets other programs run. Android and iOS are two operating systems for phones. An app is one of those other programs, and it runs on top of the system. Keep this picture in mind, because we will come back to it, and it will help you a great deal when the next part comes up, so hold on to it.

Someone has to build each one. Apps are made by developers, who may work alone or in a team. Developers use special tools to build and fix them, such as Android Studio and Xcode. They write in programming languages such as C, Python and C++. A program is first written in a computer language by a person and then translated into a form the computer can run. That is a lot of steps. Read each of these words slowly, and say them out loud if that helps you to remember them.

Many of them work with a machine somewhere else, one you may never see, and it could be a long way off. A server is a computer on a network that stores things like files and sends them to other devices. Network-connected apps often use HTTP to send and receive data. The phone sends a request, and a server answers each request with a response. A database is a repository of information that a server can pull content from to build a page or screen. You may not see any of this. It all happens in a flash, out of sight, while you wait for the page to show up on the screen.

Here are some dates. The iPhone first appeared in 2007, and Apple opened its App Store in 2008. People get apps from an online app store. As of November 2026, Apple handles payments and hosting for apps in its App Store, so developers do not have to build their own store. As of November 2026, Apple also reviews apps before they appear on its App Store. Keep those dates in mind, because stores can change as the years go by. Read the dates once more, and say them out loud, so that they stay with you for a long while.

How does a developer make money? As of November 2026, developers can earn money from an app by charging for the download or for features inside it. Some apps and some things inside apps cost real money. That is worth knowing before you tap on anything. It is a good thing to think about before you press a button, so ask what a tap might cost. In-app purchases let a person pay for extra things inside an app. Some apps offer auto-renewable subscriptions, which the App Store has supported since 2011.

Sometimes a phone asks you a question, and it may pop up out of the blue. An app can ask for permission before it uses the camera or contacts on a phone, and you can say Allow or Deny. Apps may ask for permission to use information on a device, such as contacts, calendar entries and location. On Android, a person can let an app use their location only while they are using that app. That is one choice among several, and it is yours to make. A phone's settings let a person change an app's permissions after they first answered.

Your information can travel, and it helps to know how. Some apps share information from a phone with other companies that show ads based on a person's location and interests. Taking out apps you no longer use helps avoid unnecessary data collection. Updating one gives you the latest features and makes it more secure. Many software updates are made to fix security risks, and a phone can be set to update its apps automatically. Malware is software made on purpose to cause harm. It is good to know the word, so you can spot it when you hear it, and so you know what people mean by it.

Before you get an app, ask a grown-up, every time. Parents can set up a phone so that a child has to ask a grown-up before getting an app. Some phones have settings that let a parent make a child ask permission before downloading or buying apps. Parents can block or allow particular apps on a child's phone. Apps and games can have an age rating, and parental controls can block games and apps by their rating. Ask first, every time you want a new one.

Words to know

• developers: app makers
• server: sending computer
• database: stored information
• permission: being allowed
• malware: harmful software