Soft matter encompasses materials that show flow and deformation properties intermediate between Newtonian liquids and crystalline solids. An interesting class of soft material is the dense particulate suspensions, formed by dispersing solid particles in a Newtonian liquid at high volume fractions, which have attracted significant recent interest in the field of stimuliresponsive materials. Some of the dense suspensions show a shear-induced, reversible increase in viscosity known as shear thickening (ST). Depending on the particle volume fractions and applied stresses, many of these systems show a remarkable transformation from a liquid-like state to a solid-like state called shear jamming (SJ). In this thesis, we explore the relaxation dynamics and shear-induced deformations in ST and SJ suspensions using shear rheology and in-situ optical imaging. We uncover the microscopic mechanism controlling the stress relaxation in the SJ state and highlight the importance of shear-induced particle scale plasticity. We establish an intriguing correlation between the nature of transient relaxation and the steady-state shear jamming phase diagram. We further study a novel, structural memory in the SJ systems that survives the dramatic stress relaxation by orders of magnitude during jamming/unjamming transition. We point out the significance of the shear-induced local rigid clusters that encode such memory in these systems. Next, we explore the shear thickening in the fractal particulate suspensions that has several technological advantages over the conventional shear thickening systems. Using different types of fractal fumed silica particles, we highlight the importance of fractality, complex particle geometry, and structural entanglement in controlling the shear thickening properties. Finally, we study the signature of stress induced transition from a frictionless to a frictional transition in ST and SJ systems following a recently proposed scaling relation.