Black hole X-ray binaries (BH-XRBs) are gravitationally bound associations of a compact object (black hole) and a normal star. The compact object can `accrete' matter from the companion star forming an accretion disk which releases tremendous energy, predominantly in X-rays. The stages of sudden bursts of X-ray activity in these systems are commonly known as 'outbursts'. The present thesis endeavours to comprehend the accretion process underlying the exceptionally bright outbursts observed in the two galactic BH-XRB sources: MAXI J1820+070 and 4U 1543-47. The investigation utilizes a wideband spectro-temporal analysis, employing multi-instrument X-ray data. The findings of this study propose the presence of a complex corona geometry (extending both radially and vertically) for MAXI J1820+070 during the 2018 outburst. Additionally, our research reveals a remarkably strong and dynamic absorption feature between 8-11 keV in the 4U 1543-47 spectra. This detection represents the first occurrence of its kind in X-ray binaries. We hypothesize that this feature arises due to the absorption of accretion disk photons by a highly ionized, relativistic disk wind, which attains speeds up to 30% of the speed of light.