Most people use apps every day, so here is how one works, from the person who makes it to the moment you tap it. An app is short for application, which is a software program, and it can help people play games, read the news or find their way. Software is the programs a computer runs, and hardware is the equipment. A phone's main software is its operating system, which manages a computer's resources and lets other programs run. Android and iOS are two operating systems for phones.

Apps are made by developers, who may work alone or in a team, and they use special tools to build and fix them, such as Android Studio and Xcode. Programs are written in languages such as C, Python and C++. A person writes a program first in a computer language, and then it is translated into a form the computer can run.

The iPhone first appeared in 2007, and Apple opened its App Store in 2008. In the first 60 days after that opening, more than 100 million apps were downloaded, and by January 2010 more than three billion had been downloaded. Developers can earn money from an app by charging for the download or for features inside it, as of November 2026.

Some apps and some things inside apps cost real money. In-app purchases let a person pay for extra things inside an app. You may have heard that apps are always free. In fact, some apps, games and music cost real money, so a child should ask a grown-up first.

Here is where a server comes in. A server is a computer on a network that stores things like files and sends them to other devices, and in a client-server system the client sends a request and the server sends back a response. A database is a repository of information that a server can pull content from to build a page or screen.

As of November 2026, Apple reviews apps before they appear on its App Store, and Apple handles payments and hosting for apps there, so developers do not have to build their own store. Apple also says that apps that cheat the review system can be removed and the developer expelled from its developer program.

Apps may ask for permission to use information on a device, such as contacts, calendar entries and location. An app can ask for permission before it uses the camera or contacts on a phone, and you can say Allow or Deny. A phone's settings let a person change those answers later, and on Android a person can let an app use their location only while they are using that app.

You may have heard that an app can use anything on a phone. In fact, the Android system follows the principle of least privilege, so by default each app can reach only the components it needs. On Android, a person can also choose how long an app may use location, camera or microphone, such as only while using the app or asking every time.

Some apps share information from a phone with other companies that show ads based on a person's location and interests. As of November 2026, Apple's App Tracking prompt lets a person tell an app not to track them, and then the app cannot get the system advertising identifier. You may have heard that saying no to tracking makes an app stop working. In fact, as of November 2026, on iPhone a person can tell an app not to track them and still use its full features.

Before a child gets an app, a grown-up should be asked. Parents can set up a phone so that a child has to ask a grown-up before getting an app, and some phones have settings that let a parent make a child ask permission before downloading or buying apps. As of November 2026, Apple's Ask to Buy is turned on by default for children under 13, and the parent can approve or decline a request from the parent's own device.

Parents can also block or allow particular apps on a child's phone. A parent can set daily time limits on a child's phone, and Google's Family Link can also set a bedtime. On Apple and Google phones, a parent or guardian creates the account for a child under 13.

The CISA, a U.S. cybersecurity agency, advises getting apps only from official app stores such as the device maker's or the operating system's store. Updating an app gives you the latest features and makes it more secure, and many software updates are made to fix security risks. A phone can be set to update its apps automatically.

Apps and games can have an age rating. Parental controls can block games and apps by their rating, and on Google Play they can limit what is downloaded by maturity level. As of November 2026, developers must answer age rating questions honestly so that an app works properly with parental controls.

Words to know

• server: network computer
• database: information store
• developers: app makers
• permission: your say-so