Well, it could be that Naruto is cursed by a strange jutsu during a mission. Turning into a girl, he first has a hard time getting used to his new body. His friends initially don't recognize him. But then they notice some of his old mannerisms. He might then use his new form to his advantage, like getting closer to some female characters who were previously guarded around him and learning their secrets.
One possible plot could be that Naruto turns into a girl to infiltrate an all - female organization that is suspected of having ties to a new threat. As a girl, he has to deal with the different social dynamics among the women, like cattiness in some cases but also strong sisterly bonds. He also has to hide his true identity while trying to gather information.
In a fanfiction like this, Naruto could turn into a girl as part of a training exercise gone wrong. His new female form makes him see the world from a different perspective. He realizes how differently people treat him now. Some guys start hitting on him, which he finds really annoying at first. But as time passes, he starts to understand the female experience better and uses this new understanding to become a better ninja and a more empathetic person in general.
Chapter 338, "The Adulterer is Far on the Horizon, Yet Close Before the Eyes", is the clearest early answer because it turns Li's situation into a concrete plot event. Early on, Tang Jinyu, dressed in a light apricot Cheongsam, sat indifferently....
Chapter 210, "Are All of Jiang Li's Fans Hidden Big Shots?", is the clearest early answer because it turns Miss Jiang's situation into a concrete plot event.
Chapter 587, "Has He Also Become a Part of the Play?", is the clearest early answer because it turns Isn's situation into a concrete plot event.
Chapter 137, "Lai Fu's Death Has Another Cause", is the clearest early answer because the violence around Aunt Ying becomes final instead of hypothetical. Early on, Jiang Li personally went to Lai Fu's tomb and performed a small....
Chapter 306, "I Believe Whatever Miss Jiang Says!", is the clearest early answer because it turns Jiang Says's situation into a concrete plot event.
Chapter 669, "My First Love Sister Who Died Young", is the clearest early answer because it turns Xi Yang's situation into a concrete plot event. The chapter turns that into something concrete by moving from Bang," the door closed, but Chen Qijun's words lingered in Tai Fan's...
Chapter 265, "This Time You Must Help Me", is the clearest early answer because it turns Weibo's situation into a concrete plot event.
Chapter 700, "As long as the money is in place, I am willing to do anything!", is the clearest early answer because it turns Shao Changqing's situation into a concrete plot event.
Chapter 404, "The Vice Dean of Hua Country Chinese Medicine University?!", is the clearest early answer because the rescue effort creates visible on-page results. A useful checkpoint is the way the scene starts with Several minutes later, Jiang Li doubled back and knocked on Huo...
Chapter 317, "You Can't Afford to Mess with the Person Behind Her!", is the clearest early answer because it turns Yu Yiyang's situation into a concrete plot event. A useful checkpoint is the way the scene starts with He Pingzhang gazed at the man curled up before him, unable to...