It takes an input of energy to convert liquid to vapour ,so increse

[alnywk]

it takes an input of energy to convert liquid to vapour ,so increse the entropy
if an increase in entropy is natural, why does this not happen naturally with less effort on its own?

 

[Galileo]

Because, like you said. It takes an input of energy, which no longer makes it an isolated system. Entropy will maximize itself in an isolated system under the given constraints. One of them is conservation of energy.