Commission XII focuses on arc welding processes and production systems for promoting better practical applications in various industrial fields. Scientific and technical contributions by Commission members emphasize sensors and process control, advanced arc welding process and underwater welding, production systems and applications, as well as quality control and safety of arc processes. Together with Study Group-212, the Commission works to establish more reliable welding and joining technologies with higher productivity through a deep understanding of the physical phenomena governing the arc welding processes. Commission XII covers the application of the arc welding process to various fabrication fields based on fundamental issues of arc physics and the production systems for various industry sectors to realize low-cost production with high quality. Good practices presented at Commission XII can be spread worldwide and published as state-of-the-art papers in Welding in the WorldThe recent activity has focused on the research and development of digital manufacturing with use of sensors and process control, Internet of Things and wire-arc additive manufacturing for innovative joining technologies to realize high-efficiency manufacturing.