Dear student,
As we know physical changes are reversible in nature but chemical changes are irreversible in nature.
So formation of cloud is a physical change because as the water evaporates it goes in the air and form clouds by the process of condensation and again back to earth by the process of precipitation. As here water is changing its state from liquid to gas and then gas to liquid. Here, only its physical property is changing so we can say that it is a physical change.
Regards