Instagram is a free mobile app for sharing photos and videos instantly with friends, family, and colleagues. To create an account, users download the app and can sign up using their Facebook, phone number, or Gmail account. Once signed up, users can add photos to their profile, connect to Facebook to find people to follow, and select tabs like Home, Search, Likes, and Camera to navigate the app. Posts can be edited, filtered, captioned, tagged, and shared to social media accounts.