If Naruto gains a Zanpakuto, it would completely change the power dynamics in the Naruto universe. Naruto is already extremely powerful with his chakra and Sage Mode, etc. A Zanpakuto would add a whole new dimension to his combat abilities. He might be able to use its unique powers in combination with his shadow clones, for example, sending clones out with the Zanpakuto's special abilities to surprise opponents. It could also potentially give him new ways to deal with different types of jutsu and enemies.
Naruto might get a Zanpakuto that complements his existing powers. Since he has a strong connection to wind chakra, it could be a Zanpakuto with wind - based abilities. Maybe it could create powerful tornadoes or slices of wind that are sharper than his normal Rasengan - infused attacks.
Yes, there are likely fanfictions out there where Naruto has a zanpakuto. Fanfiction writers often like to cross over different anime concepts. They might give Naruto a zanpakuto from the Bleach universe to explore new storylines and character developments. It can lead to really interesting scenarios where Naruto has to learn to use the zanpakuto's powers, which are quite different from the chakra - based abilities in Naruto's original world.
At first, Naruto would be clumsy with it. He has no prior experience with Zanpakuto. But his determination would drive him to practice. He'd study how to hold it properly, how to swing it effectively. Maybe he'd even talk to it like he does with his friends, trying to understand its spirit if it has one.
Maybe it's a mysterious traveler from a far - off land. This traveler recognizes Naruto's potential and strength of character and gives him the three zanpakuto as a means to help Naruto protect his village and the people he loves.
Maybe a zanpakuto with the power to heal. Naruto is all about protecting his friends and village. So a zanpakuto that can heal wounds during battle would be very useful. It could also have a secondary ability to boost the chakra of his allies. This would fit with Naruto's selfless nature.
It could be that the zanpakuto was brought into Naruto's world by some sort of interdimensional rift. Naruto, being curious and always eager to grow stronger, is immediately drawn to it. His godlike perception allows him to sense the latent power within the zanpakuto. He might seek out help from characters who have some knowledge of different power systems, like Kakashi. Together, they could try to decipher the mysteries of the zanpakuto, leading to Naruto adding yet another powerful tool to his already impressive arsenal.
One possibility is that Naruto would be very curious about the zanpakuto. He would start to experiment with it right away. He might try to infuse it with his Rasengan, creating a new and powerful attack. This would be a unique blend of Naruto's ninja skills and the power of the zanpakuto.
In a Naruto finds a zanpakuto fanfiction, it could lead to some really interesting crossovers. Naruto might initially be confused by the strange weapon. He could try to use it in his own unique way, perhaps combining his chakra with the zanpakuto's power. Maybe he'd seek out someone to teach him about it, like if he somehow ended up in the Bleach universe and found Ichigo to help him understand the zanpakuto better.
He could have his Rasengan - like power. Maybe the wielder could call upon a spirit - version of the Rasengan to attack opponents. It would be a powerful and concentrated blast of energy.