What is an .ipa file
.ipa files are iOS apps
All the apps for iPhone, iPad and iPod Touch comes with .ipa extension, whether it’s a game or any other app.
.ipa files can also be extracted like a ZIP file. All you have to do is rename the file. For example, Telegram.ipa can be renamed as Telegram.zip, and you can extract the file to check what it contains.
When you download an app from the App via iTunes on Mac or Windows, it keeps the back of the app as .ipa file. You can install the app connecting your phone to computer.