The purpose of this article is to review modern developments in four-dimensional (4D) printing, discuss what it is, investigates new applications that have been suggested and discovered its future impact. Additive manufacturing of intelligent/ smart dynamic structures, i.e. 4 Dimensional Printing technologies have attracted interest day to day since it was conceptualized first in the year 2013. This technology uses the creation of live 3D objects from multi-material 3D printers.4D printing technique uses the conversion of static 3D printed structure from smart materials (Shape changing/memory materials) into a dynamic one by application of external stimuli like heat, water, light pH, magnetic field etc. Nowadays, these dynamic 4D printed structures are widely used for manufacturing smart devices, actuators, smart textiles, smart shoes, and smartphones. This emerging field is becoming popular, day to day because it finds significant applications in Engineering as well as in biomedical fields like biomimetic printing, tissue engineering, smart sutures, drug delivery, artificial stents etc. A detailed review of 4DP technology, its processes, materials used with applications in different fields is carried out in this paper.