Hi Parameswaran! To begin with.. If you are from a programming background, try to understand the programming language which you are more familiar and comfortable with. As a mobile app developer, your apps will likely be written in popular programming languages such as Objective C, C++, C# or Java.  The specific choice of language naturally depends on what mobile platform and OS it is they are creating the apps for.  For example, if is for Apple's iOS, they would need to know how to use Objective C, whereas Java is the language to acquire proficiency in for Android Apps. If you are from a non-programming background, then naturally, a basic training of programming fundamentals, can be your starting point. Next, as you might already know, “It's all about the platform”. Try to identify the platform you want to develop for, i.e. iOS, Android or Windows. Choosing Android/Windows can be easy as it is free of cost and majority of the audience use these OS. To start developing for iOS, first, Get a Mac. Yes, you need a Mac. It’s the basic requirement for iOS development. Second, Xcode is the only tool you need to download. Xcode is an integrated development environment (IDE) provided by Apple. Third, you will need to have a device to test. Of course, you can test anytime on the simulator, but a device is highly recommended. And lastly, you will need to enrol in iOS Developer Program, which is optional. The iOS Developer Program costs US$99 per year. Without joining the iOS Developer Program, however, the simulator is the only mean to run your apps. You can’t deploy and test the app on your device. Needless to say, you’re not permitted to submit your app to App Store. In other words, you can’t sell your app!! I hope, this gives you an overview of the mobile app development field and also a heads on to start with. Goodluck!!