Computer software plots magnetic field lines by starting from points of high magnetic field strength and calculating the density of lines to represent flux density. Users can click on specific points to generate lines, but this method may not accurately reflect the actual flux density. A more systematic approach involves plotting lines based on the curvature of the magnetic field, with denser lines in areas of greater curvature. The software's effectiveness can vary, and users have shared experiences with different applications, including one that performs well for drawing field lines. For those seeking specific software setups, links and recommendations are being exchanged in the discussion.