User Flow Mapping is the practice of diagramming the path a user takes through a product to accomplish a goal. Flows show screens, interactions, decisions, and alternative paths. A checkout flow might be: Browse → Add to Cart → View Cart → Enter Shipping → Enter Payment → Confirm Order → Success. Flows identify where users succeed and where they get stuck. You create flows for key user scenarios (sign-up, checkout, onboarding, refund). Each flow shows decision points (if user is logged in, do this; if not, do that) and alternative paths (user abandons, user retries after error). Flows guide design and help teams discuss UX before building.