One possible plot could be that Naruto and Hinata travel back in time to their childhood days. They could use their knowledge of the future to prevent some of the tragedies that happened. For example, Naruto might try to stop the Nine - Tails attack on the village in a different way, and Hinata could help by using her Byakugan skills more effectively from an earlier age. They would also have the chance to change their own relationship dynamics. Maybe Hinata could be more confident around Naruto earlier, and Naruto could realize his feelings for her sooner.
Perhaps they travel back to a time during the Fourth Great Ninja War. With their future knowledge, they could find ways to end the war more quickly and with fewer casualties. Naruto might be able to reach out to the enemies in a different way, and Hinata could support him. Their married relationship would add a new layer to their interactions. They could work as a team more effectively than they did before, and their love could be a source of strength for the other ninjas around them.
Another plot could be that they go back to a time just before Naruto leaves for his training with Jiraiya. Hinata could decide to go with him this time. This would change Naruto's training experience completely. They could train together, and Hinata could learn new skills from Jiraiya as well. Their relationship would grow even stronger during this time away from the village. And when they return, they could be a more powerful couple, ready to face any challenges that come their way in the new future they are creating.
One possible plot could be that Naruto and Sakura, after getting married, are somehow sent back in time to their early days at the ninja academy. They have to navigate their past selves while also trying to figure out a way back to their own time. Naruto might use his knowledge of future events to prevent some tragedies, and Sakura could use her medical skills in new ways in the past.
A plot could be that they time - travel to a period when a great war was about to start. Naruto and Ino would then work together to gather intelligence using Ino's mind - link abilities and Naruto's combat skills to infiltrate enemy camps. They would try to find a way to stop the war before it fully breaks out, and during this journey, their relationship deepens even more, and they realize how much they mean to each other, which was already strong from being married in their original time.
Well, it could be about them traveling back to prevent a great disaster that was supposed to happen in the future. Maybe something related to the destruction of the Hidden Leaf.
Well, a plot twist could be that Hinata is actually from a future where something bad has happened, and she came back in time to marry Naruto secretly to change the future. Maybe in the original timeline, Naruto dies or the village is destroyed, and their secret marriage is a key to prevent that. Also, there could be a character who is jealous of their relationship and tries to expose their secret marriage, creating all kinds of chaos and drama.
Well, perhaps in a fanfiction, Sasuke could be on a mission and get injured. Hinata, who is also on the same mission (for some reason), takes care of him. This act of kindness makes Sasuke see her in a new light. They start to bond over their shared experiences and their understanding of the ninja world. Eventually, they fall in love and marry. Their married life could then be about protecting the village together and dealing with any threats that come their way.
One possible plot could be that they have a secret wedding. Since both are quite private people in their own ways. They don't want a big fuss, so they hold a very small ceremony in a secluded part of the forest near the village. Only a few very close friends are invited, like Naruto and Shikamaru. After that, they have to deal with the reactions of the rest of the village when they find out, which could be a mix of surprise and happiness.
A simple plot could be that Hinata gets injured while on a mission, and Naruto takes it upon himself to nurse her back to health. During this time, they have long conversations and get to know each other on a deeper level, leading to the start of their romantic relationship.
They could witness historical events. For example, Naruto might see Minato become Hokage. Hinata could see how her family's status was in the past. It would be interesting to see how they interact with their parents. Naruto might be eager to show off his skills to his father, while Hinata would probably be more reserved in front of her family.
Well, their relationship would likely become more confident. Since they are already married, Hinata wouldn't be as shy around Naruto as she was in the original timeline. Naruto would also be more aware of Hinata's feelings and his own for her. He would probably be more protective of her right from the start.
In a Naruto and Hinata get married fanfiction, they might have a big, traditional shinobi - style wedding. All their friends from Konoha would be there, like Shikamaru, Sakura, and Kakashi. They would celebrate with lots of food and dancing.