Forward modeling techniques are essential for understanding spectral line behavior under varied physical conditions. In this presentation, I will give an overview of current forward modeling tools for solar coronal emission lines, with an emphasis on P-CORONA, a state-of-the-art, publicly accessible code. P-CORONA simulates the intensity and polarization of forbidden and permitted lines using three-dimensional magnetohydrodynamic models of the corona. It includes magnetic effects through the Hanle and Zeeman processes and accounts for non-linear solar wind velocities. I will highlight key results from P-CORONA analyses of spectral lines from UV to IR, relevant to instruments such as Aditya-L1/VELC and DKIST. Finally, I will discuss how these tools can be used to study the influence of physical parameters on coronal line emission, test and refine theoretical models through comparisons with observations, and support instrument design by predicting which spectral lines and polarization signals are most useful for specific science goals.