During the early days of mobile applications, we had to rely on native technologies to build reliable apps, that too separate apps for each platform, but we now have a lot more options. Cross-platform frameworks started popping up over the last few years. Frameworks like Xamarin and Ionic gained popularity in the early days and the tools have matured with the addition of React Native and more recently Flutter.
Flutter is an open-source UI software development kit created by Google which is used to develop native like apps for Android, iOS, Linux, Mac, Windows, Google Fuchsia, and the web from a single codebase.