Guys like girls for the same reason that girls like guys.

Genetics, Hormones, Nature, Nurture, and a desire to perpetuate their genetic lineage.

Animals do not question this.

If you want to know what guys find particularly attractive in a girl, this varies between guys the same way it varies with girls.

Me, I like tits and nice eyes. Someone else may like blond hair and money.

Same with girls, some girls like big dicks and tight abs, others may like longer hair and a special talent.