Accretion of gas through a disc onto a black hole is associated with many active phenomena in our universe such as active galactic nuclei (AGNs), X-ray binaries (XRBs), and extra galactic jets. Based on temperature, black hole accretion discs can be divided into two distinct classes: hot and cold. Hot accretion flow consists of optically thin, and geometrically thick disc with very low mass accretion rate. Hot accretion flow is very common in the universe, ranging from low-luminosity active galactic nuclei (LLAGNs), which is the majority of nearby galaxies, to the quiescent and hard states of black hole X-ray binaries. On the other hand, the thin disk and slim disk models belong to the class of cold accretion flows and both consist of optically thick gas. One of the most interesting topics in recent years in this field is wind (often called outflow). Wind is not only a fundamental aspect of accretion flow, but also plays an important role in AGN feedback, since wind can suppress the star formation and black hole growth effectively.