The nearby isolated molecular clouds are the compelling laboratories to study the evolution of globules and the various processes of star formation. Magnetic field plays a crucial role in the evolution of these molecular clouds as well as it affects the star formation processes. Hence a comprehensive study of magnetic field towards these molecular clouds is required to understand these processes. In this thesis, we have studied the magnetic field geometry and strength in various environments of molecular clouds e.g., cloud-cloud collision scenario, bright-rimmed clouds (BRCs), high-latitude clouds etc. When unpolarized starlight passes through the intervening interstellar dust grains that are aligned with their short-axis parallel to the local magnetic field, it gets linearly polarized. The plane-of-the-sky magnetic field component can, therefore, be traced by doing linear polarization measurements of background stars projected on the clouds. We have chosen the regions to map magnetic field geometry on the basis of two different classifications of star formation, triggered and spontaneous. Triggered star forming regions e.g. cometary globules, bright-rimmed clouds are mainly associated with HII regions having a high mass star in the center of it. When massive star forms it photoionizes the surroundings, forming HII regions, that display highly irregular structures such as filaments, pillars, CGs and BRCs. In the radiation-driven implosion (RDI) mode of triggered star formation, the incoming ionizing radiation from that massive star further compresses these small clouds to collapse and make them gravitational unstable to form new stars. We have chosen a HII region Sh2-262 having multiple BRCs to map the magnetic field geometry and strength. On the basis of magnetic field lines orientation in these BRCs we compared our result with the MHD simulations and studied the RDI mode of triggered star formation. More so, we compared these results with the previously studied HII regions, Sh2-131, Sh2-185, Sh2-236 and Sh2-126. Along with magnetic field study, to understand RDI processes, we performed molecular line observations using four lines in two BRCs having different orientations of magnetic field lines with respect to the incoming ionizing radiation. We carried out optical and NIR spectroscopic observations to estimate the mass accretion rates in young stellar objects associated with triggered star forming regions and compared them with non-triggered star-forming regions like Taurus. Furthermore, we made an optical design of Wide-field polarimeter (Wi-Fi Pol) for 1.3m Devasthal Optical telescope and developed a polarimetric data reduction pipeline.