The world is undergoing a paradigm shift in how products are manufactured. The fourth industrial revolution, or Industry 4.0, is given greater importance by industries and companies worldwide as they bridge the gap between technology and manufacturing processes. Digital manufacturing has become a key research area as it can boost the productivity of all manufacturing processes by using advanced techniques such as machine learning, the Internet of Things, and artificial intelligence. These techniques have been used in tandem with numerous hybrid additive manufacturing processes to increase precision, create unlimited complex geometries, reduce material waste, change the constraints of the part during manufacturing if needed, and reduce the capital requirement. However, conventional welding techniques were harmful to humans, provided a poor surface finish, and proved difficult for welding complex parts. With hybrid additive manufacturing techniques combined with conventional welding techniques, conventional welding processes have been automated, reducing human intervention. This can be done using some of the latest technologies and concepts invented, such as robots, cobots, artificial intelligence, and virtual reality. Some of these new concepts and technologies, such as machine learning, virtual reality, and the Internet of Things, can optimize various welding parameters and improve remote welding technology. In addition, this paper thoroughly explores four important IT-based domains of digital manufacturing used in welding processes: robots, the Internet of Things, machine learning, and artificial intelligence. These concepts have influenced traditional welding processes by presenting the various parameters used to examine the impact. In addition, this paper also considers the potential scope of research. Also, this paper would look at different digital manufacturing processes and how they are used to make hybrid parts based on additive manufacturing.