Naruto might give Itachi some traditional Konoha food as a gift. Since Itachi has been away from the village for a long time, he might miss the taste of home.
One popular fanfiction might involve Itachi passing on a unique jutsu to Naruto. For example, a Sharingan - related power that Naruto can use in a creative way against tough enemies. This could change the dynamics of his battles and how he is perceived in the ninja world.
Naruto would adapt to Itachi's life in several ways. Socially, he'd have to get used to Itachi's connections and rivalries. For instance, his relationship with Kisame would be different as Naruto. He might try to influence Kisame in a more positive way. Emotionally, he'd have to deal with Itachi's internal struggles. Itachi had a lot of guilt and secrets, and Naruto would have to either come to terms with them or find a way to resolve them. And in terms of combat, he'd practice Itachi's signature moves over and over to make sure he could use them effectively in battle.
At first, it's likely to be very awkward. Naruto is a very open and energetic person, while Itachi is more reserved. But as they are forced to spend time together because of the arranged marriage, they start to find common ground. For instance, they both care deeply about protecting the village in their own ways.
I'm not sure about a specific one off - hand, but you can check out fanfiction websites like Fanfiction.net or Archive of Our Own. Just search for 'Itachi gives Naruto power' and you'll likely find a bunch of different stories. Some might focus more on the action aspect, while others might explore the emotional side of Itachi's decision to give Naruto power.
Naruto might initially be shocked and angry. He has a strong sense of justice and being kidnapped goes against everything he stands for. He would likely try to fight back immediately, using his basic ninja skills and his determination. For example, he could try to use his Shadow Clone Jutsu to create distractions and escape.
One possible plot twist could be that Naruto struggles to control Itachi's power at first. Since Itachi's power is very different from his own chakra nature. For example, Itachi's genjutsu abilities might be too much for Naruto to handle initially, leading to him accidentally using it on his friends, causing mistrust among them. Another plot twist could be that the Akatsuki targets Naruto more aggressively, believing he has become a greater threat with Itachi's power. They might send their most powerful members after him, like Pain or Obito. Also, Naruto might discover some hidden secrets about Itachi's power that even Itachi was unaware of, which could change the course of the shinobi world's power balance.
Well, it could mean that Itachi, a character, has been the inspiration for a lot of fan - created fictional stories within the Naruto universe. Maybe Itachi has certain traits or actions in the original Naruto series that make him a popular subject for fans to write their own made - up stories about, and these stories are filling the Naruto fanfiction world related to him.
In some fanfictions, it could be through a special jutsu or ritual. Maybe Itachi, before his death, transferred his Sharingan to Naruto in a unique way, perhaps using a forbidden technique that was known only to a few in the Uchiha clan.
Itachi's protectiveness can make Naruto more confident. Knowing that someone as powerful as Itachi has his back gives Naruto a sense of security. This allows him to take more risks in his training and battles, which in turn helps him grow stronger. For example, he might attempt more difficult jutsu without fearing too much about the consequences of failure because he believes Itachi will step in if things go really wrong.