In the continuation of the TMDs materials study it is important to explore their distinct structural properties as well as the impact of the defects on their physical properties. Because the material's structural properties could define their possible utility for the specific purpose and modifications in structural configurations that also makes them more specific or general for their potential applications. Therefore, herein one has discussed the structural properties of different forms of the TMD materials, such as bulk TMDs structure, individual triple layers structure, polymorphs structures, distorted structures, and a single layer or few layers structure including a description of the different phases and phase transition, stability, patterning, and tunability of TMDs materials. Moreover, a few possible significant types of defects have been also taken into account, such as point defects, doping, and grain boundary. Herein, one has also briefly discussed the impact of impurities on the TMDs’ electronic transport and metallicity, magnetic characteristics, and optical properties, additionally, also kept a short description of the effect of impurity on bilayer TMDs.