In recent years, Additive Manufacturing (AM) has revolutionized the manufacturing sector by offering efficient production and the flexibility to create complex designs. While AM is widely used across various industries for its advantages, achieving high surface quality remains challenging. Surface defects such as partial melts, porosity, and staircase defects often hinder the performance of AM-produced components. Various post-processing techniques have been employed, including conventional methods like mechanical polishing and non-conventional techniques like chemical finishing and laser polishing. However, each method has limitations, particularly in polishing complex geometries or avoiding harmful chemicals. Plasma electrolytic polishing (PEP) is a non-contact process that utilizes a salt-based electrolyte and has emerged as a promising solution to enhance the surface finish of AM components, especially complex and tiny parts. PEP produces highly reflective and smooth surfaces with improved corrosion resistance, making it suitable for aerospace, medical, and energy applications. Recent studies have proposed theories to explain this mechanism through a combination of electrochemical reactions and plasma discharge, where the formation of a vapor-gaseous envelope (VGE) and its interaction with the anode surface led to preferential removal of surface roughness and burrs. The mechanism is further influenced by factors such as the Ohmic effect, cavitation-like phenomena, and the varying temperature distribution during the process, which collectively contribute to surface smoothing. Other researchers have highlighted the different types of charge carriers that lead to material removal and, hence, surface smoothing. Additionally, researchers have investigated the impact of various process parameters on the PEP process, including voltage, electrolyte temperature, and polishing time. The material removal mechanisms, recent advancements in polishing additive components, and future research directions are discussed comprehensively. PEP is still a novel process; the role of various parameters on VGE generation and its effect on roughness improvement still needs investigation numerically and experimentally. PEP is still a novel process; the role of various parameters on VGE generation and its effect on roughness improvement still needs investigation numerically and experimentally.