In this communication, we present some of our recent results on spatially structured optical beams, their nonlinear interactions, and their direct transfer to quantum states for applications in quantum information science and technology. Our investigations primarily focus on optical vortex beams, which form the basis of most experiments discussed herein. We generated optical vortex beams with various topological charges using spiral phase plates at a fixed wavelength. These beams were then frequency-converted into optical vortex beams or hollow Gaussian beams at new wavelengths via second-order nonlinear parametric processes. Employing an optical parametric oscillator (OPO), we demonstrated flexible transfer of the topological charge from the pump beam to the signal and idler beams, tunable across a broad range of the electromagnetic spectrum. Furthermore, we explored the transfer of the topological charge of the pump to single photons and characterized the divergence properties of single photons carrying orbital angular momentum (OAM). We also generated full Poincaré beams by superposing vortex beams of different topological charges with Gaussian beams having orthogonal polarization. These beams exhibit all possible polarization states, as represented by points on the Poincaré sphere. To analyze these beams, we developed a novel method to quantify the polarization coverage of full Poincaré beams. Additionally, we generated Poincaré–Bessel beams and discovered that such beams can be understood as superpositions of an infinite number of full Poincaré beams.