What is the function of interfacing in sewing?

Interfacing plays a crucial role in sewing by reinforcing specific areas of a garment, such as collars, cuffs, and button plackets. This added support helps these parts maintain their shape and structure, which is especially important for well-fitted and professional-looking garments. By providing stability, interfacing ensures that areas subjected to stress or wear retain their intended form over time, contributing to overall durability and quality in clothing construction. This process enhances the garment's functionality without altering the fabric's intended design or style.

The other options do not align with the primary purpose of interfacing. For instance, while adding warmth or creating volume might be relevant in certain contexts, those are not functions of interfacing. Similarly, while interfacing can impact the appearance of a fabric, its main purpose is not decoration but rather structural reinforcement.