According to the plot, static friction force has a maximum magnitude of around 3.0 N, and kinetic friction has a magnitude of about 1.5 N.
The plot appears to be telling you the force required to get the yellow block moving along the table. If one applies less than 3.0 N of force, the block remains motionless. But as soon as it starts to slide, one need only apply 1.5 N of force to keep it moving (presumably at a constant speed).
