What would adding external protrusions to a wing do?

Adding external protrusions to a wing, such as winglets or vortex generators, can enhance aerodynamic performance by improving airflow over the wing's surface. These modifications can help reduce drag, increase lift, and improve maneuverability by controlling airflow and minimizing vortex formation at the wing tips. Additionally, they can enhance stability and efficiency during flight, particularly at high angles of attack. Overall, external protrusions optimize the wing's performance characteristics.