Ratzon is the spiritual state associated with the lowest of the three heads of keter, the Reisha d'Arich ("the extended head").
With regard to the power of will, it is said "nothing stands before (the force of one's) will," and "there is nothing as forceful as will."
In the partzuf of Arich Anpin (the outer partzuf of keter representing the general power of will in the soul), the "origin of will" is associated with its "crown" or its "skull" referred to as the gulgalta. At this level, "there is no reason (rationale) for will." However, in the intrinsic wisdom of Arich Anpin, referred to as mocha stima'ah("concealed brain"), there exists "a hidden (unexpressible) reason for will."
The higher level of will, totally superrational in nature, serves to control and direct (from above and without) all of the conscious and rational powers of the soul, beginning with the intellect, the soul's base of rationality itself. The lower level of will, possessing a hidden rationale, is the origin of the soul's power to willfully pursue those objectives rationally chosen by the mind. The first is referred to as ratzon lma'alah mita'am vda'at and the second as ratzon al pi ta'am vda'at.
The Divine ratzon finds its essential expression in the commandments given to Israel in the Torah. In our own Divine service, when we devotedly perform G-d's commandments purely because they are the expression of His essential will (lma'alah mta'am vda'at), we connect ourselves to the first level of G-d's will. In our conscious intentions, based upon the secrets and mysteries revealed to us in Kabbalah with regard to the spiritual effects of each commandment in particular, we connect ourselves to the second level of G-d's will.