https://www.techradar.com/news/instagram-now-supports-app-based-two-factor-authentication

You can now secure Instagram account with two-factor login using third-party apps like Google Authenticator. This means that, as well as your password, you'll need to enter an app-generated code each time you want to log into your account.

This helps ensure your account isn't compromised if Instagram ever falls foul of a data breach. It also helps you avoid account breaching via phishing attacks.