A user flow is a visual representation of how users navigate through an app or website, essential for guiding users towards specific goals such as purchases or sign-ups. It involves understanding business objectives, user needs, and creating mockups and prototypes to refine the paths users take. User flows are not always linear, often containing decision points and barriers influenced by user preferences and external factors. Effective design includes A/B testing, utilizing shapes for clarity, providing visual feedback, and identifying key engagement moments, known as "aha moments," to enhance user experience. Analyzing these flows through tools like Heap allows designers to optimize the user journey and improve conversion rates by understanding user interactions and preferences.