Naruto would probably be very friendly and kind. He has a big heart, so he'd likely greet her with a big smile and start chatting right away, asking her name and where she's from.
Perhaps the little girl is a prodigy but is being bullied because of her abilities. Naruto discovers her crying in an alley. He comforts her and tells her his own story of being an outcast as a kid. He helps her gain confidence. They might start training together secretly. The little girl could then use her new - found confidence and skills to impress the other kids in the village, all while Naruto watches with pride.
I suggest 'The Girl Who Changed Naruto'. Here, the girl Naruto finds has a very different view of the ninja world. Her ideals clash with Naruto's at first, but through their interactions, they both grow and eventually fall in love. It's a fanfiction that really delves into character development.
He could decide to protect the baby girl himself. Naruto has a big heart. He might see the baby as someone he needs to look after, just like how he was always looking out for his friends. Maybe he starts teaching her some basic ninja skills when she grows a bit older.
One possible fanfiction could be about Kushina finding Naruto in a situation where he's lost in a forest. Maybe she uses her unique chakra sensing abilities to track him down. It could be a heartwarming story of a mother reuniting with her son.
One possible scenario in this fanfiction could be that Naruto discovers an ancient and mysterious shrine in the forest. The shrine might hold some sort of power or secret. Maybe it has a connection to the Sage of Six Paths. Naruto, being his curious self, would likely start to explore it. He might find strange markings or artifacts inside that he has never seen before.
There's a fanfiction where Naruto finds a girl who is a healer. She tends to his wounds after a tough battle. Their relationship starts from this simple act of kindness. As time goes on, Naruto realizes her importance in his life not just as someone who heals him physically but also someone who understands his emotional turmoil.
Well, if Sasuke finds out Naruto is a girl in fanfiction, it could completely change their dynamic. Maybe Sasuke would start to see Naruto in a new light, perhaps more protectively. Their relationship might become more romantic as Sasuke realizes his feelings for Naruto are different from what he thought. It could also lead to some interesting plot twists, like Sasuke having to re - evaluate his rivalry with Naruto.
His life would become a lot busier. Taking care of a baby is no easy feat. He'd have to balance his ninja duties with looking after the baby. For example, he might have to cut short his training sessions or decline some missions at first.
One common plot is Kushina finding Naruto in a different time or dimension. For example, she might end up in the future where Naruto has grown up and she gets to see the kind of person he has become. It's an emotional and interesting concept as she gets to witness all his achievements and the challenges he has overcome.