FlutterFlow offers a range of prebuilt features but recognizes that unique app requirements may necessitate customization beyond its default capabilities, which is where Custom Actions come into play. Custom Actions allow users to write Dart code to extend app functionalities, enabling integration with unique services, special logic, or interactions not available out of the box. Creating a Custom Action involves defining input arguments, writing the code, and testing it within the app’s action flows, ensuring reusability and flexibility across the project. Users are encouraged to start with small, focused actions, document their code for collaboration, and leverage external packages for enhanced functionality. Real-world applications of Custom Actions include calculating shipping costs in e-commerce apps, integrating third-party APIs for personalized user experiences, and creating reusable logic for analytics tracking, affirming Custom Actions as a powerful tool for tailoring apps to specific needs while maintaining the speed of visual development.