Additive manufacturing (AM) in general and 3D printing technology in particular have been effectively applied to many fields such as education, life applications and industrial applications. AM and three-dimensional (3D) printing allow the manufacture of products with complex shapes that would be difficult or even impossible to process using traditional machining methods. For example, for machining the mold cavities and cores with conformal cooling channels in the plastic injection mold, only the AM and 3D printing methods are suitable. AM and 3D printing are the core technologies of Industry 4.0, where technologies are used to improve the efficiency of operations and improve product quality; and of Industry 5.0, where technologies are used to improve the value of the products for customers. With the trend of mass-customized production and the complex parts, AM is selected as the core manufacturing method for fabricating the parts. This chapter presents technical advances such as AM and 3D printing systems based on artificial intelligence techniques, solutions, and existing standard systems to improve the efficiency and quality of AM and 3D printing technology in industrial applications, especially in manufacturing parts made of plastic, metal, or mixed materials. On the other hand, testing methods to evaluate product quality during and after the printing process are also mentioned.