Which of the following best describes forming in manufacturing?

Forming in manufacturing primarily involves the process of changing the size and shape of a workpiece without removing material. This process can include various techniques such as bending, forging, rolling, and extruding, where the material is physically manipulated to take on a new form while retaining its overall mass. The emphasis here is on the transformation of the material's geometry through applying force, which distinguishes forming from other manufacturing processes that may involve cutting or joining.

In the context of forming, the focus is on modifying the workpiece through processes that typically do not involve material removal, thus making it distinct from options like cutting materials or joining parts together. While altering surfaces for aesthetics may play a role in manufacturing, it does not encapsulate the fundamental concept of forming itself. Hence, the option describing the change in size and shape accurately captures the essence of what forming entails in manufacturing.