Download the Instagram app from the App Store (iPhone) or Google Play Store(Android). 2. Once the app is installed, tap to open it.

Instagram (@instagram)

Instagram is a free photo and video sharing app available on iPhone and Android. People can upload photos or videos to our service and share them with their followers or with a select group of friends. They can also view, comment and like posts shared by their friends on Instagram.

There is no right or wrong answer to this question - both are correct! Some people might prefer to say "in Instagram" because it sounds more like you're talking about the app itself, while others might say "on Instagram" because it sounds like you're talking about using the app to post photos.