The standard form of a line equation is Ax + By = C, where A and B are not both equal to zero. To graph a line in standard form, find the x-intercept by setting y = 0 and solving for x, and find the y-intercept by setting x = 0 and solving for y. These two intercept points are then plotted and connected to graph the line. The document provides an example of finding the x-intercept (4,0) and y-intercept (0,-6) of the line 3x - 2y = 12.