How does a wing create lift?

There is no practical wing of infinite span. However, the characteristics of such a wing can be measured on a section of wing spanning the width of a wind tunnel, since the walls block spanwise flow and create an effectively 2-D flow. By definition, the reaction force is resolved into two components. That parallel to the incident airflow is the drag and that normal to the incident airflow is the lift. At practical angles of incidence the lift greatly exceeds the drag.