Every technology uses an IDE right? Such as Eclipse, Netbeans etc. The IDE for Mendix is called studio pro. It is a collection of tools that are supported by Mendix, where you can ;

1. Create application
2. Drag and drop components to your app/page
3. Managing security
4. Create business logic for your app and many more

It is recommended to use Mendix studio pro that has an LTS – Long Term Support for production applications. You can download studio pro from here.